Zhou Jielun is a good __________.[ ]
A. sing
B. sings
C. singer
答案:C
鼻腔粘膜温度一般保持在()
A.33℃~35℃
B.36℃~38℃
C.31℃~33℃
D.29℃~31℃
E.31℃~33℃
循环流化床锅炉运行时床温降低的原因是什么?