So far no life has been found outside the earth, but while some scientists are actively searching for living things in outer space, others firmly believe there ____ .
A.mustn’t be B.may not be C.can’t be D.won’t be
I drink a cup of coffee________；but usually I take tea.
A.frequently B.often C.constantly D.occasionally
At first sight，Tom ________in love with Mary. Two months later，he ________her.
A.was；married B.fell；married
C.was；was married to D.fell；married with
As is well known，Edison was one of the greatest scientists________.
A.all the time B.all time C.of all time D.of all the time
Anna was reading a piece of science fiction，completely ________to the outside world.
A.having been lost B.to be lost C.losing D.lost
________enough preparations，they thought it better to put off the trip till next week.
A.Not making B.Having not made C.Not having made D.No made
