Q - How can we be in the final seven years because the two Witnesses are not here yet?

A - Because the two Witnesses do not come to earth until the second half of the final seven years.

The Holy Spirit is not taken from the earth. He is taken "out of the way,"

Regarding the Two Witnesses:

Rev 11:2-15 (NLT)
2 But do not measure the outer courtyard, for it has been turned over to the nations. They will trample the holy city for 42 months.
3 And I will give power to my two witnesses, and they will be clothed in burlap and will prophesy during those 1,260 days.
4 These two prophets are the two olive trees and the two lampstands that stand before the Lord of all the earth.
5 If anyone tries to harm them, fire flashes from their mouths and consumes their enemies. This is how anyone who tries to harm them must die.
6 They have power to shut the sky so that no rain will fall for as long as they prophesy. And they have the power to turn the rivers and oceans into blood, and to strike the earth with every kind of plague as often as they wish.
7 When they complete their testimony, the beast that comes up out of the bottomless pit will declare war against them, and he will conquer them and kill them.
8 And their bodies will lie in the main street of Jerusalem, the city that is figuratively called "Sodom" and "Egypt," the city where their Lord was crucified.
9 And for three and a half days, all peoples, tribes, languages, and nations will stare at their bodies. No one will be allowed to bury them.
10 All the people who belong to this world will gloat over them and give presents to each other to celebrate the death of the two prophets who had tormented them.
11 But after three and a half days, God breathed life into them, and they stood up! Terror struck all who were staring at them.
12 Then a loud voice from heaven called to the two prophets, "Come up here!" And they rose to heaven in a cloud as their enemies watched.
13 At the same time there was a terrible earthquake that destroyed a tenth of the city. Seven thousand people died in that earthquake, and everyone else was terrified and gave glory to the God of heaven.
14 The second terror is past, but look, the third terror is coming quickly.
15 Then the seventh angel blew his trumpet, and there were loud voices shouting in heaven:

Notice that in Rev 11:2-3 Jerusalem is trampled for 42 months. This is the 2nd half of Daniel's 70th week after the "abomination of desolation", and the same 1260 days that the Two Witnesses prophesy. This is further confirmed by Rev 11:7-14 which shows that the Two Witnesses will be killed and then raised up at the end of their testimony, and Rev 11:15 which shows this happening just prior to the 7th Trumpet, which occurs at the end of the 2nd half of Daniel's 70th week, and the loud voices are shouting in heaven "The whole world has now become the Kingdom of our Lord and of his Christ, and he will reign forever and ever." This is immediately prior to the Second Coming. The conclusion has to be that the Two Witnesses prophesy during the 2nd half of Daniel's 70th week (Great Tribulation).

Identity of the Two Witnesses:

Malachi 4:5 "Look, I am sending you the prophet Elijah before the great and dreadful *Day of the LORD arrives"(NLT). 2 Kings 2:11 "And it came to pass, as they still went on, and talked, that, behold, [there appeared] a chariot of fire, and horses of fire, and parted them both asunder; and Elijah went up by a whirlwind into heaven"(NLT).

It is a virtual certainty that the identity of one of the Two Witnesses is Elijah. The second one is probably Moses based on his presence on the mount of transfiguration (Matt 17:3). Premillennialists agree that this scene with Moses and Elijah is a preview of the coming glory of the Lord Jesus Christ. Rev 11:6 "They have power to shut the skies so that no rain will fall for as long as they prophesy. And they have the power to turn the rivers and oceans into blood, and to send every kind of plague upon the earth as often as they wish"(NLT). Power to shut the skies is exactly what Elijah did. Power to perform plagues is exactly what Moses did in Egypt. Moses was the great lawgiver and Elijah was the greatest prophet. Together Moses and Elijah represent the law and the prophets. Matt 7:12 "...This is a summary of all that is taught in the law and the prophets"(NLT).

*Day of the LORD Wrath of God begins at the Seventh Seal of Revelation after there is silence in heaven for half a hour (Rev 8:1,2), and includes all of the 7 Trumpet and 7 Bowl Judgments that follow. Since Elijah comes before the "Day of the Lord" according to Mal 4:5, and since the Two Witnesses prophesy during the Great Tribulation and not before, then the "Day of the Lord" Wrath of God cannot be in the first half of Daniel's 70th week. The Lord Jesus Christ himself names the first half of Daniel's 70th week "The Beginning of Sorrows/Birth Pangs"(Matt 24:8). It will be just like the examples of Noah and Lot. Removal/Rapture, then the Wrath of God immediately starts. Luke 17:26-29 "When the Son of Man returns, the world will be like the people were in Noah's day. In those days before the flood, the people enjoyed banquets and parties and weddings right up to the time Noah entered his boat and the flood came to destroy them all. And the world will be as it was in the days of Lot. People went about their daily business, eating and drinking, buying and selling, farming and building until the morning Lot left Sodom. Then fire and burning sulfur rained down from heaven and destroyed them all" (NLT).

The conclusion has to be that since the Wrath of God is not in the first half of Daniel's 70th week, then neither can the Rapture (main rapture of the Church) be in the first half of Daniel's 70th week.

However the "Open Door" in Rev 4:1 is before the first seal is open and that is when the antichrist will go forth, this is "the hour of temptation" and those Christians that are right with God who has made him number one in their lives will not have to wait till the second half of the tribulation that's the reason Jesus Christ said he will put before them an "Open Door" before the hour of temptation this is to say before God sends ANYTHING on this earth.

Rev 4:1

After this I looked, and, behold, a door was opened in heaven: and the first voice which I heard was as it were of a trumpet talking with me; which said, Come up hither, and I will shew thee things which must be hereafter.

This open door is the first rapture and it will take place early in the first half of the final seven years. The second rapture will be sometime around midpoint of the final seven years.