绝缘手套的试验周期是()。
A.每年一次;
B.每月一次;
C.六个月一次;
D.三个月;
参考答案:C
下列句中各有一处错误,指出并改正。
1. He lives nearest to the school,so he has the short journey.
2. Betty is friendly with us.
3. He is born in Shanghai in 1998.
4. Do you see the chair have three legs?
在平面构成里,渐变就是指()的逐渐改变。
A.位置
B.形体
C.方位
D.方向