例句：

　　It was incumbent on them to attend.

　　他們必須出席。

　　Our children attend the same school.

　　我們的孩子上同一所學(xué)校。

　　There are plans to extend the no-smoking area.

　　現(xiàn)已有擴大無煙區(qū)的計劃。

　　The meat is chemically treated to extend shelf life.

　　豬肉經(jīng)過化學(xué)處理以延長保存期。

　　Careful maintenance can extend the life of your car.

　　精心保養(yǎng)可延長汽車壽命。