Where the Skylab will fall?
A. is kept secret
B. has been made public
C. has been predicted by scientists
D. can’t be predicted even by computers
将一枚硬币投掷两次,至少出现一次正面的概率为()。
A. 0.25
B. 0.5
C. 0.75
D. 1
A.M1B-1B.MIB-2C.MIB-3D.MIB-4
A. M1B-1
B. MIB-2
C. MIB-3
D. MIB-4
Cats sleep much more than horses do partly because cats ________.
A. need more time for restoration
B. are unlikely to be attackers
C. are more active than horses when they are awake
D. spend less time eating to get enough energy