锅炉组成中下降管主要是把锅筒内的水输送到下集箱,供给水冷壁管足够的循环水量,下降管也可直接吸收炉膛的热量。( )
参考答案:错
Michael is fond of _____, but I prefer _____.[ ]
A. travel; read
B. travelling; reading
C. to travel; to read
D. travelling; read
咽后壁组织瓣的长宽比例应设计为()
A.1:1
B.1.5:1
C.1:1.5
D.2~3:1
E.4:1