人们使用过的人体实验类型不包括的是()
A.志愿实验
B.自体实验
C.安慰实验
D.欺骗实验
E.强迫实验
参考答案:C
--- Where is your grandpa now?
--- He ______ newspaper in the living room.
A.read
B.is reading
C.was reading
D.reads
乙炔气柜至冷却塔之间管道内的乙炔气体是双相流动的。