为练习写了文

１．你掉下冰淇淋的话，別吃它。
２．虽然他吃健康的食物，他的肚子痛了。
３．我需要戴我的外衣。要下雨了。
４．上班了以后超人想休息了。
５．消防员戴头盔保护他们的头。

1 如果冰淇淋掉地上的话，就别吃了

2 虽然 他吃的食物很健康，但是他突然开始肚子痛了

3.Not bad, but you need to understand the difference between "戴" and “带”

  戴：you wear the coat now.  带：you just take the coat with you, and wear it when it rains.

  So for this sentence I think you should replace "戴"with“带”，then we will have a better standing of it

  Also for this sentence if you speak it out,there will be no difference, because  "戴" and “带” share the same pronunciation in Chinese.

4.I do not undertand 

5.Good

Above all, except sentence 4, I can truly understand them as a Chinese, so I think you do not need to take a long time to understand why I have to modify your sentence 1 and 2 like that, as long as I can understand what you say that will make sense, it also apply to how I learn English, when I truly understand what other people saying in English and speak English they can understand it will be a big step...