More and more attention has been drawn to the fact that many children are ________ in the countryside when their parents flood into the cities for jobs.

A．left off

B．left aside

C．left out

D．left behind

航迹推算在（）情况下可以暂时中止？

A．航经危险物附近

B．航经狭水道和渔区

C．遭遇大风浪

D．航经雾区