《梦游天姥吟留别》的作者是（）。

A.李白

B.杜甫

C.苏轼

D.杜牧

When carrying out a parallel track search pattern，the course of the search units should normally be which of the following（）.

A.In the same direction as the anticipated drift

B.In the opposite direction of the anticipated drift

C.Perpendicular to the line of anticipated drift

D.Downwind