根据句意，用所给单词的适当形式填空。
我们在新的旅行启程之际，不应忘了我们来自何处．
As we on our new journey， we shouldn't forget where we came from．
但是，说实在的，现在他已经有一段时间没玩了．
…but， be ， he has not played for a while now．
在扔掉废物前进行分类是必要的．
It's necessary to divide the waste into different kinds before we it ．
成功的关键在于从错误中学习，并且永不放弃．
The key to success is to learn from your mistakes and never ．
我们历史老师中等身高．他对我们很严格．
Our history teacher is of medium ．He is very with us．