一道英语题?请给出正确解释,谢谢!
问题描述：
一道英语题?请给出正确解释,谢谢!
It is required that such insulator(绝热体）_____ a reat resistant material.
A:must be made ofB: should be made of
C:will be made ofD: would be made of
答
B 前是要求require ,后面应该用should 用中文也想得通.