_______ late 1990’s about two thousand adults were enrolled in correspondence study in the community.

Pigeons can carry messages for about ______.A．two weeksB．four weeksC．two yearsD．four years

There are ______ Russian（s) and ______ American（s) on board.A．one, oneB．one, twoC．two, two

－－－－ Could you please tell me something about the two _________？－－－－ _____. They are exchange studen

完型填空There were once three sons of a wealthy businessman. ___1___ they met, the two eldest,who were twins, ___2___ to quarrel about which of them should be his father’s heir （继承人).

When the writer talks about two ships and two trains, he is______.A．recalling his past exp

It s getting rather late. It s time we______ home.A．are goingB．wentC．goD．must go