—John got injured in the game.

—Would it be at least a fortnight ______ he could recover and return to school?

A．when

B．that

C．since

D．before

机油压力不足，主要是机油量不足，此外，还有机油滤芯不良，（）等原因

A、仪表不准确

B、机油加油口盖不牢固

C、机油滤芯器脏污堵塞