在()的堤段,渗水在背河堤坡的薄弱处集中流出,可能形成漏洞。
A.高水位
B.堤坡陡
C.偎水时间长
D.透水性大
E.截渗效果好
参考答案:A, B, C, D
若2a=3,2b=4,则23a+2b等于( )
A.7
B.12
C.432
D.108
The country life he was used to _____ greatly since 2000. [ ]
A. having changed
B. has changed
C. changing
D. have changed