问题情境
参考答案:指的是具有一定难度,需要学生努力克服,而又是力所能及的学习情境。
The business was _____ by his grandfather.[ ]
A. put up
B. stood up
C. got up
D. set up
《爆破安全规程》规定:一般爆破,交流电不小于(),直流电不小于2A。
A.2.0A
B.2.5A
C.3.0A
D.3.5A