塔机可用吊钩直接挂吊物，严禁用塔机运送人员。
参考答案：错
给你一个凸透镜，你如何测出它的焦距？
--How is Tom, do you know ?--____.
A．He is very clever.
B．He’s right
C．He is much better
D．He is a doctor
