—The one with _____ umbrella? She is our monitor.
A:the; a
B:the; an
C:a; an
D:a; the
56×30=____ 30×25=____ 69×20=____ 25×8=____
34×60=____ 80+42=____ 0×879=____ 47×7=____
35×20=____ 79×30=____
从方框中选出下列句子的应答语。
A.Hello.
B.I am from China.
C.OK!
D.My name is Mike.
E.Nice to meet you too.
54÷6=____
54÷9=____
设向量a→、b→,满足|a→|=|b→|=1,a→•b→=﹣12,则|a→+2b→|=( )