问题详情：
根据所给的英语解释，用合适的单词填空。
1. Tom is always an honest boy. I never (be not sure if something is true) what he says.
2. How could Jack make such a mistake? I can’t (form a picture in one’s mind of something or somebody) what he had in his mind.
3. We should go easy on (对……宽容) that young boy. It’s not good to be too
(making sure the rules are obeyed) with him all the time.
4. To solve the problem, the first step is to find out what the (reason) is.
5. My grandpa (start to have a skill, ability, etc.) the habit of jogging in the morning many years ago.
【回答】
1. doubt 2. imagine 3. strict 4. cause 5. developed
知识点：其他
题型：完成句子
