两个乘数分别是4和7,写成乘法算式是( )或( )。
4×7;7×4
4. I’m poor at English, so to make a speech in English at the meeting is ________ my ability.
A.above
B.outside
C.over
D.beyond
在地面自动起动中,什么时候开始自动点火()
A、N2 16%
B、N2 20%
C、N2 26%