关于θ角,表达式正确的是()。
A、tanθ=tanβ/sinφ
B、tanθ=tanα/sinφ
C、tanθ=tanα/sinβ
D、tanθ=tanβ/cosφ
参考答案:B
My brother _____ to the ground while ____ his bicycle and hurt his leg .
A. falls; is he riding
B. fell; he was riding
C. fall; he is riding
D. felt; was he riding
表皮内的淋巴细胞主要是()
A.CDT细胞
B.CDT细胞
C.CDT细胞
D.B细胞