In our class, when the bell rang and the teacher closed his book, it was a ______ for everyone to stand up.
A.signal
B.chance
C.mark
D.measure
In the market, vegetables are sold by _______ kilogram, I mean, by _______ weight.
A.the; 不填
B.不填; 不填
C.the; the
D.不填; the
By the end of April, Peter _______ here for three months.
A.will have stayed
B. will stay
C.stays
D.has stayed
A great number of students _______ said they were forced to practice the piano.
A.to question
B.to be questioned
C.questioned
D.questioning
—I can’t repair these until tomorrow, I’m afraid.—That’s OK, there’s _______.
A.no problem
B.no wonder
C.no doubt
D.no hurry
Health problems are closely connected with bad eating habits and a _____ of exercise.
A.limit
B. lack
C.need
D.demand
About ______ gene-targeting drugs are already in testing pipeline. It won’t be long ______ they are put into effect.
A.two dozen; before
B.two dozens; that
C. two dozens of; before
D.dozens; that
The news shocked the public, _______ to great concern about students’ safety at school.
A.having led
B.led
C.leading
D.to lead
I _______ to visit you later that day, but I had to phone and cancel.
A.come
B.came
C.am coming
D.was coming
_______ our manager objects to Tom’s joining the club, we shall accept him as a member.
A.Until
B.Unless
C. If
D.After