分牙簧的弯制用()
A.0.4mm钢丝
B.0.5mm钢丝
C.0.6mm钢丝
D.0.7mm钢丝
E.以上均可
参考答案:B
—Who _____ a pet in your class?
—Many boys _____. [ ]
A. has; do
B. have; do
C. have; does
D. has; are
已知Q入=50×104m3/d,Q出=48,Q出=48104m3/d,Q存=1.5104m3/d,则输差是()%.
A.1
B.0.1
C.2
D.0.5