—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→|=（ ）
