A number of experts ________ invited, but the number of the experts who attended the conference ________ only 20．

1. A.
   were; was
2. B.
   was; were
3. C.
   was; was
4. D.
   were; were

A number of new machines were introduced from abroad，______ an increase in production.

A．resulted inB．to result in   C．result inD．resulting in

A number of questions will be discussed by the students      beginners of English fail to use the language

properly.

A．which           B．as              C．why            D．Where

A number of the increasing population makes us surprised.

            A                B           C       D

A number of students____  attending the meeting now and the number of students _____more than 100.