Be sure to ______ your wife when you come here this evening.

—Do you mind if I read the newspaper on the table？ —________________.

A.Good news for you

B.Go ahead, please

C.Yes, sure

D.No, I can’t

A.Where are you going？

B.What are your plans for summer vacation？

C.What are you doing？

A.Δ/Δ

B.Yo/Yo

C.Yo/Δ

D.Δ/Yo

YO/YO接线的电压互感器，一次A相熔断器熔断，其二次侧Vbo、Vco()的电压正常，()和Vac电压很低，但不等于零。

A.WO

B.YO

C.KO

D.KG

A.as

B.if

C.while

D.that

设f(x，y)与φ(x，y)均为可微函数，且φˊ(x，y)≠0，已知(xo，yo)是f(x，y)在约束条件φ(x，y)＝0下的一个极值点，下列选项正确的是()．

A．若fˊx(x，yo)＝0，则fˊy(xo，yo)＝0

B．若fˊx(xo，yo)=0，则fˊy(xo，yo)≠0

C．若fˊx(xo，yo)≠0，则fˊy(xo，yo)＝0

D．若fˊx(xo，yo)≠0，则fˊy(xo，yo)≠0

设f(x，y)与ψ(x，y)均为可微函数，且ψˊy(x，y)≠0，已知(xo，yo)是f(x，y)在约束条件ψ(x，y)＝0下的一个极值点，下列选项正确的是()

A．若fˊx(xo，yo)＝0则fˊy(xo，yo)＝0

B．若fˊx(xo，yo)＝0则fˊy(xo，yo)＝0

C．若fˊx(xo，yo)≠0则fˊy(xo，yo)≠0

D．若fˊx(xo，yo)≠0则fˊy(xo，yo)≠0