以R134a为制冷剂的制冷装置压力容器进行液压试验时，最合适的试验介质是（）。
A.矿物油
B.水
C.酯类油
D.醚类油
参考答案：C
一个数除以4，商是12，余数最大是l2．______．（判断对错）
—Excuse me, sir. Is there a young man named Liu Guozheng living here?
—I'm sorry, madam. He lives here ______. He moved to another place last month. [ ]
A. once upon a time
B. no longer
C. at last
D. all the time
