1971年，( )提出一般系统理论。
A．平克斯
B．赫恩
C．贝塔朗菲
D．米纳罕
E．杰曼
参考答案：C
My parents _____ in Hong Kong. They were born there and have lived nowhere else. [ ]
A. live
B. lived
C. were living
D. had lived
呼吸困难者不一定有发绀表现。（）
