金属喷涂是利用()等热源,将喷涂材料熔化后,喷射到修复件表面的。
A.电加热
B.电感应
C.辐射
D.电弧
E.火焰
参考答案:D, E
根据对话内容,在每小题的空白处写出一个完整的句子,使对话意思完整。
John: Oh, Tom. Please don't sit on this chair!
Tom: 1. ?
John: Look! One of its legs is broken. It's dangerous to sit on it.
Tom: 2. . Who's broken it?
John: I don't know. I found it this morning when I was cleaning the floor.
Tom: Let's tell our teacher about it and then someone can repair it.
John: No. 3. .
Tom: Yourself? Have you learnt to repair a chair?
John: Yes. My father is a worker. He is good at repairing things. 4. .
Tom: Oh, your father taught you. 5. ?
John: Certainly. Let's begin.
下列植物属于单轴分枝的有()
A.雪松
B.柏树
C.水杉
D.小叶榕