有电击危险的环境中使用的手持照明灯和局部照明灯应采用()的安全电压。
A.24V或36V
B.42V
C.127V
参考答案:A
同义句改写。
1. It took him 300 yuan to buy the bike.
He ______ 300 yuan ______ the bike.
2. My grandpa died two years ago.
My grandpa ______ ______ ______ for 2 years.
3. She found it hard to take care of the baby.
______ was hard for her ______ ______ ______ the baby.
4. I was pleased with what he did.
What he did ______ ______.
5. The Reads went to New York three years ago.
The Reads ______ ______ in New York for three years.
一般说来,力的作用位置不是一个几何点而是有一定大小的一个范围。