问题

_______ entering the classroom, remember to take your seat and turn off your cell phone
A:At
B:From
C:Upon
D:As
B:From
C:Upon
D:As
正确答案是:
同类题型
Nearby were two canoes______ they had come to the island[ ]
I would appreciate _____if you can keep an eye on my dog while I am away.[ ]
It is broadcast that the opera Catsat the Theatre Royal on 19th March
He got up late this morning. There _______no time to have breakfast.
The new car won’t go into production soon. The engineof it hasn’t been fully ___.