单项选择题
A. confusing B. confused C. with confusion D. to confusion
Had electronic computers not been invented, many proble...
单项选择题Had electronic computers not been invented, many problems of space flight（）now.
A. could not have been solved B. could not be solved C. must not be solved D. should not have been solved
There has been a decrease（）the number of students enter...
单项选择题There has been a decrease（）the number of students entering the Medical College this year.
A.on B.over C.in D.of
"I'm too tired, but let's go.""Why（）rest a while?"A.don...
单项选择题"I'm too tired, but let's go.""Why（）rest a while?"
A.don't we B.not let's C.not we D.let's not
