平行于面的应力称为切应力,用符号()表示。
A.σ
B.β
C.γ
D.τ
参考答案:D
When I attended a meeting in Beijing I ___ my old teacher’s house.
A.called on
B.called at
C.visited at
D.visited on
正常成人胆囊超声测量的前后径一般不超过()
A.2.0cm
B.2.5cm
C.3.0cm
D.3.5cm
E.4.0cm