用所给词的适当形式填空。
1.You should read their(instruct) first before you start to use these machines.
2.In the end,he(overcome) all of the difficulties and realized his dream.
3.After(graduate) from the famous university,he found a job as a lawyer successfully.
4.I didn't understand what he said(clear),so she explained it to me again.
5.We are looking forward to(meet) you again.
He used to _____ problems _____ along with his classmates,but he can get on well with them now.
句意为：他过去和他的同学们相处有困难，但是他现在能够和他们相处得很好。 used to意为“过去常常”，后面跟动词原形；have problems doing sth. 为固定搭配，意为“做某事有困难”。故选选项C。
— Can you spare time to come to our Thanksgiving party?
— Well,I don't know _____.
宾语从句要用陈述句语序，先排除选项B、D；再结合语境可知此处表示“我不知道那时我是否能完成我的工作”，故所缺的内容是选项C。