最早的鸡每年产的卵只有8~12个,而现在的许多种产卵鸡每年可产卵二三百个,进化的原因是

A．食物不同的结果

B．自然选择的结果

C．人工选择的结果

D．生存环境的结果

用所给单词的正确形式填空。（共10小题；每小题1分，满分10分）

小题1:Look at your __________(foot). They are very dirty(脏的).

小题2:Tom’s English is not good. I think he should __________(read) English every day.

小题3:There are many ___________(different) between you and me.

小题4:He is________________(babysit) his sister this evening.

小题5:Jack ___________(exercise) every day. So he looks very strong.

小题6:He _________(send) me the postcard two days ago.

小题7:It is important __________(get) up early in the morning to do sports.

小题8:I am not _____________(feel) well at this moment.

小题9:Let’s take _________(walk) after dinner.

小题10:I always brush my_______(tooth) after meal.