— ______________ are those?
— They are flowers.
A. Who
B. Where
C. What
D. What's
答案:C
皮肤结核的特点,除外()。
A.狼疮结节
B.溃疡
C.脓疱、丘疹
D.瘙痒
E.瘢痕
由阀门全开的条件算出在要求流量为Q时所需扬程为He,在离心泵的性能曲线上查得与Q对应的扬程为H,H>He,在流量为Q时泵的效率为η,则泵的轴功率N为()。
A.QHeρg/1000ηkW
B.QHρg/1000ηkW
C.QHeρ/102ηkW
B.QHρg/102ηkW