在多点顶升飞机时,两个主要顶起点必须在()。
A.机尾
B.机头
C.机翼
D.机头和机尾
参考答案:C
—It shouldn’t take long to clean up after the party if we all volunteer to help.
—That’s right. ________.
A.Many hands make light work
B.Something is better than nothing
C.The more, the happier
D.The sooner begun, the sooner done
在后张预应力混凝土梁孔道中水泥灌浆的强度应按设计要求,如设计无要求时,不得低于( )。
A.20MPa
B.30MPa
C.25MPa
D.35MPa