生物体由小长到大的原因是（　　）

用方框中所给动词的适当形式完成下列句子。

I ____my teeth three times yesterday.
When I was a child, I ____ to be a doctor.
We ____ our vacation last year. We stayed at a very nice hotel.
Amy's grandfather____ when he was 90 years old.
The concert ____ at 7:30 and ended at 10:00.

读某地区等温线示意图，回答下面小题