[观察例句]
观察下列句子，指出黑体部分的动词形式及语法作用。
1．The look on his face showed that he felt astonished.动词ed形式作表语
2．My special hobby is collecting stamps.动词ing形式作表语
3．He is more interested in science than in art.动词ed形式作表语
4．My job is teaching English.动词ing形式作表语
5．Our next aim is to help farmers increase food production.
动词不定式作表语
6．Your task today is to wash the curtains.动词不定式作表语
