Bài 1 :Put the verbs in brackets in the past simple tense os past perfect tense
1. Neil Armstrong and Buzz Aldrin (collect).................... some moon dust samples before they (return)............. to Earth.
2. By the time Yang Liwei (become)................. the first person sent into space by the Chinese space program in 2003, NASA already (send).................... over 100 people.
3. After the spaceship Soyuz 37 (be)............. in orbit around the earth, Pham Tuan and Viktor Gorbatko (conduct)...................some experiments.
4. When we (arrive)..................... in Kennedy Space Center, the space shuttle already (launch)................. into space.
5. Dennis Tito already (complete)............... 900 hours of training by the time he (fly)...............into space in 2001.
Bài 1 :Put the verbs in brackets in the past simple tense os past perfect tense
1. Neil Armstrong and Buzz Aldrin (collect)......had collected.............. some moon dust samples before they (return)....returned......... to Earth.
2. By the time Yang Liwei (become)........became......... the first person sent into space by the Chinese space program in 2003, NASA had already (send)........sent............ over 100 people.
3. After the spaceship Soyuz 37 (be).......had been...... in orbit around the earth, Pham Tuan and Viktor Gorbatko (conduct)........conducted...........some experiments.
4. When we (arrive)...............arrived...... in Kennedy Space Center, the space shuttle had already (launch)....been launched............. into space.
5. Dennis Tito had already (complete).......completed........ 900 hours of training by the time he (fly).........flew......into space in 2001.