Hép me plz mai cô kiểm tra rùi ạ ;-; ai làm nhanh nhất +đúng nhất thì ctlhn nhá . Thanks trước 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.