There have been some problems but basically it's a good system.

　　雖然出現(xiàn)過一些問題，但這基本上仍不失為一個好系統(tǒng)。

　　His family have been a very positive influence on him.

　　他的家庭對他有十分良好的影響。

　　There have been many changes in recent years.

　　近幾年發(fā)生了許多變化。

　　I'm doing some research on the subject.

　　我正就這一課題進(jìn)行研究。

　　How will the company be doing ten years further on?

　　十年以后公司的情況將如何呢？

　　He's doing very well at school.

　　他在學(xué)校里學(xué)習(xí)很不錯。