This time I want to do ____ . A．differen

下面的算式中，去掉括号后不改变计算结果的是（　　）

A．（60+40）+1

B．（36-20）÷2

C．28×（10÷5）

D．80÷（4×5）

I’d like to see you off at the airport. Could you tell me _____ ?

A．when your plane took off

B．when did your plane take off

C．when your plane takes off

D．when does your plane take off

急性腹痛伴休克．最常见的病因是()

A．急性心肌梗死

B．大叶性肺炎

C．胃、十二指肠溃疡穿孔

D．急性坏死性胰腺炎

E．急性坏疽性胆囊炎

LM曲线的斜率由什么决定？LM曲线在什么情况下移动？

平面锉削一般使用（）等方法.

A.交叉锉、拉锉

B.顺向锉、推锉

C.交叉锉、顺向锉和推锉

D.推锉、拉锉