下列哪种物质具有过敏毒素作用（）。
A.C3a、C4a、C5a
B.C3b、C4b
C.C1～C9
D.C1q
E.C2b
参考答案：A
His face（）with pain when badly hurt by the shopkeeper.
A.contracted
B.was twisted
C.was twinkled
D.twisted
