如图是几种测量工具使用后显示的情况，由图甲可知，绕在铅笔上的粗细均匀的金属丝，密绕20圈，其直径为____，由图乙可知，秒表表示的时间为____．由图丙可知，温度计的示数为____，由图丁可知，体温计的示数为____．

阅读短文，选择正确的答案。

    There are many apple trees in a garden. They're good friends. One day an old tree is ill. There are many pests in the tree. Leaves of the tree turn yellow. The old tree feels very sad and unwell. Other trees send for a doctor for him. At first, they send for a pigeon, but she has no idea about it. Then they send for an oriole(黄鹂), and she can't treat the old tree well either. Then they send for a woodpecker. She is a good doctor. She pecks a hole in the tree and eats lots of pests. At last the old tree becomes better and better. Leaves turn green and green.

①相应的骨受到牵引，

②骨绕关节转动，

③骨骼肌接受神经传来的兴奋，

④骨骼肌收缩．这些步骤发生的正确顺序是

用于飞机制造业的重要材料是(　　)