某人估测一竖直枯井的深度,从井口静止释放一石头并开始计时,经过2s听到石头落到井底的声音,由此可知井深约为()
A.10m
B.20m
C.30m
D.40m
参考答案:B
Don't laugh ___________ me. [ ]
A. to
B. at
C. for
D. in
梗阻性黄疸()
A.以间接胆红素升高为主,尿胆红素阴性
B.以间接胆红素升高为主,尿胆红素阳性
C.以直接胆红素升高为主,尿胆红素阳性,尿胆原阴性
D.总胆红素升高
E.以结合胆红素升高为主,兼有未结合胆红素升高