The news quickly spread ______ China has successfully launched another manned spaceship.

A．which

B．that

C．when

D．while

数量不多、体积小的易锈、易霉、生虫的商品应做到（）。

A．按件（箱）密封

B．货架（柜、橱）密封

C．货垛密封

D．小室密封