The first step towards _______(protect) the environment is to try to throw away less rubbish.

题目

The first step towards _______(protect) the environment is to try to throw away less rubbish.
The first step towards _______________ (protect) the environment is to try to throw away less rubbish.
用所给动词适当形式填空
填不定式可以吗?

答案

towards有两种词性：介词．副词．
这两种词性的意思都是朝着,向着的意思．
副词是用来修饰动词的,后面一般跟表示地点或者方向的词语．
在这一句中towards短语用来修饰名词step,做定语,是介词,介词后面要用动词的ing形式,所以用protecting.