* Choose the best answer in the brackets to complete the following sentences.
1. Astronauts are scientists (whom / that / Ø) travel into space.
2. They showed me the place (when / which / Ø) the spaceship landed last week.
3. The book (who / where / Ø) I’m reading is about the history of space exploration.
4. The man with (who / whom / Ø) Mr. Khoa is talking has flown into space three times.
5. The satellite (where / that / Ø) was launched into space yesterday belongs to Viet Nam.
6. David introduced me to the woman (whom / whose / Ø) husband is working for NASA.
7. 1969 was also the year in (which / when / that) the Venera 5 space probe landed on Venus.
8. The twenty-ninth of May is the day (that / which / Ø) our astronauts will be returning home.
9. The student (who / whom / Ø) was selected to join the space program is my brother’s friend.
10. The space age began in 1957 (when / which / Ø) the Soviet Union launched Sputnik 1, the world’s first man-made satellite.