散热器有（）和片式散热器。
A、圆管散热器
B、扁管散热器
C、方管散热器
D、柱式散热器
参考答案：A, B
患佝偻病的儿童主要是由于食物中缺乏[ ]
A．含钙的无机盐
B．含磷的无机盐
C．含铁的无机盐
D．含锌的无机盐
Alice had a wonderful time yesterday, ______? [ ]
A. hadn't she
B. wasn't she
C. didn't she
D. wouldn't she
