It is /has been three years ________ we left that city.

3. As Beethoven grew older, he found ______ more difficult ______________( compose ) good music.

思考：本句要考察的句型是：__________________________________________________.

常用这一句型的动词还有：______________________________________________.

　自练自提

翻译：1）我发现学习一门外语很重要。

____________________________________________________________________.

2) 我发现和他相处是困难的。

____________________________________________________________________.

3) 我认为最好是早点动身。

_____________________________________________________________________.