下列船用空调系统中冬、夏季都只能变量调节的是（）系统。
A．分区再热式单风管
B．末端电再热式单风管
C．双风管
D．末端水换热式
参考答案：C
Not only he but also his friends_______ eager to help those who lost their homes in the earthquake.
A．was
B．were
C．is
D．are
The Pharmacopoeia Of the United States Of American的缩写是
A．PUSAB．PUSC．USAD．USPE．SAP
