根据句子意思，用括号中所给词的正确形式填空，每空填一词.
You'd better think_____________ (two) before you take the final action.
The more you read, the___________(wealth) you will feel in spirit.
He was still_________(sure) how to do it though we explained all over again.
To get good grades in the exam, we should avoid___________(care)·