70年代末，美国从我国引进野生大豆与本地品种杂交，培育出抗萎黄病品种，这是利用了

A．野生大豆的抗病性状　　　

B．科技交流的成果

C．生态系统的多样性　

D．基因的多样性

用所给动词的适当形式填空

小题1:Look, there are so many people over there. What ____(happen)?

小题2:It’s seven in the morning. It’s time for us ____(go) to school.

小题3:Look at the clouds in the sky. I think it ____(rain).

小题4:___(be) everyone here?  Yes, Let’s ___(start) now.

小题5:He ___(be) be fifty years old next month. But he ___(look) so young.

小题6:Teachers’ Day ___(come) . And we ___(plan) to buy some flowers for Mrs. Li.

小题7:My mother usually ____(shop) for food on Sundays.