棉花中的“三丝”是指()
A、麻丝、棕丝、头发丝
B、麻丝、棕丝、尼龙丝
C、棕丝、头发丝、回丝
D、异性纤维
参考答案:D
Read and write. 读一读,选出正确的单词,写在横线上。
1. This is ____ (Dannys/Danny's) chair.
2. They are ____ (crayon/crayons).
3. She is ____ (read/reading)a book in the library.
4. Danny is ____ (between/below) the desk and the chair.
5. Let's ____ (be/is) good friends.
压接操作时,钳压后导线端头露出长度,不应小于()mm,导线端头绑线应保留。
A、10
B、20
C、15
D、18