地球上的陆地面积约为149000000平方千米,将149000000用科学记数法表示应为( )
A:
B:1.49×107
C:1.49×108
D:1.49×109
在Rt△ABC中,∠C=90°,若BC=1,AB=5,则tanA的值为
She could speak ________ Japanese ________ Chinese, so I had to talk with her in English.