张骞第一次出使西域的目的是  [ ]

A．联络大月氏共同夹击匈奴

B．加强同西域经济文化交流

C．寻找匈奴的去向

D．恢复对西域的管辖

The most important ______ of the farmers in Iraq is dates, of which Iraq is the world's leading exporter.

A．economic crop

B．cash crop

C．money crop

D．staple