气体通过油管柱上的()进入油管,降低管柱压力使井自喷。
A.短节
B.悬挂器
C.气举凡尔
参考答案:C
Bayfield Shopping Coupons(赠券)
小题1:What do you do to get a 10% discount at Tom’s Bookstore?
A.Spend $100.
B.Choose two books.
C.Buy some toys.
D.Present coupon No. 3.小题2:A second shirt will cost after you buy one at $180.
A.$180.
B.$168.
C.$90.
D.Nothing.小题3:If you drive to Bayfield Shopping Center, which coupon might be most useful?
A.Coupon No. 5.
B.Coupon No. 2.
C.Coupon No. 4.
D.Coupon No. 1.小题4:What are these advertisements about?
A.Things to do in a store.
B.Things on sale in a store.
C.Great fun at a shopping center.
D.Special offers at a shopping center.
A.变压器输出功率为200W
B.若n1=100匝,则输出端线圈的磁通量变化率的最大值为2Wb/s
C.副线圈两端的电压表示数20V
D.变压器的输入功率是由发电厂的输出功率决定的