若y与x-1成正比,比例系数为k1,y与x+1成反比,比例系数为k2,且k1:k2=2:3,则x的值为()。
A.A
B.B
C.C
D.D
E.E
参考答案:D
解析:
根据题意,有
The managers consider it is important that everything ________ by weekend.
A.will complete
B.has completed
C.be completed
D.is completing
预防医学的实践晚于临床医学。()