1.中文：她在弹钢琴。

(误)She was playing piano.

(正)She was playing the piano.（演奏乐器，如piano，violin，乐器前面要加定冠词the。）

2.中文：孩子们每天早上去上学。

(误)The children go to the school every morning.

(正)The children go to school every morning.（go to school是习惯用语，不加the。）

3.中文：她有一头秀发。

(误)She has a beautiful hair.

(正)She has beautiful hair.（hair指头发的整体，是不可数名词，前面不加a。）

4.中文：她喜欢看电视。

(误)She likes to watch the TV.

(正)She likes to watch TV.（看电视，习惯上TV前不加the。）