What is one of the things that must be done before man can live on Mars
A: Its surface must be studied.
B: Its temperature must be raised.
C: Big spaceships must be built.
D: Its air must be purifie
A: Its surface must be studied.
B: Its temperature must be raised.
C: Big spaceships must be built.
D: Its air must be purifie
举一反三
- All man must die, but death can vary ______ its significance. A: with B: in C: from D: on
- _________ joins the club must abide by its rules.
- What is special about adults learning a second language? A: They must spare extra efforts to learn its culture consciously. B: They must learn its grammatical structure and semantics. C: They learn it in order to communicate with native speakers. D: They recognize that variety is the spice of life.
- If your computer enters its GUI, you must use the mouse.
- When the machine is turned on for the first time,it must be sent to its home position.