在△ABC中,a2tanB=b2tanA,则角A与角B的关系是[ ]
A.A=B
B.A+B=90°
C.A=B或A+B=90°
D.A=B且A+B=90°
答案:C
I was disappointed with the film. I had expected () to be much better.
A.that
B.this
C.one
D.it
射钉枪如连续两次钉弹击发不响,需在()以后打开枪体,检查击针或击针座垫是否正常。
A.2min
B.1min
C.5min
D.10min