根据括号内的汉语提示，用句末括号内的英语单词完成句子。

1．It was in 1976 ________(我们才开始引进)this new technique．(bring)

2．________(他一定受益了)a lot from the experience of studying abroad, because his oral English has been improved greatly．(benefit)

3．________(没必要担心)even if you have never skied before．(need)

4．China has been ________(扮演着重要的角色)in maintaining international peace and security．(role)

5．Having lived in the mountain village for several month, he finally ________(习惯了早起)in the morning and sleeping early in the evening．(used)