烧结生产中加入熔剂的目的之一是为了向高炉提供高碱度烧结矿。（）
参考答案：对
单词填空
1. Flying across the Atlantic for the first time was a great _____ (achieve).
2. I'm not ______ (certainly) whether I can do it.
3. I know her_____ (fair) well, though we aren't close friends.
4. We take great _____ (proud) in your success.
5. _____ (when) you like, I'll tell you the whole thing.
The work is really very difficult; _____ it's very interesting. [ ]
A. yet
B. however
C. still
D. at the some time
