火焰加热矫正时，加热点的直径不应小于（）毫米。
A.15
B.20
C.30
D.40
参考答案：A
She is wearing a dress _______ silk. [ ]
A. made from
B. made of
C. make from
D. make of
能增加毛细血管壁通透性的体液因子是
A．心肌抑制因子
B．组胺
C．儿茶酚胺
D．血栓素A2
E．前列环素
