No one responded when Tom was speaking, so he paused _______ before continuing to draw our attention.

______ acupuncture developed, the simple “bian stones” were replaced first by stone  and pottery needles, and ________ by metal needles.

Although the country has had political independence for over a century,   it needs the support of its neighbors.

— I think it’s beneficial to build a library near our dormitory building.—  　　　. It will be a great convenience.

 We have planted thousands of trees in recent years. This year _____ we’ve planted ten thousand trees.