根据下列句子及所给汉语注释，写出空缺处各单词的正确形式，每空只写一词。To my surprise, the old man gave all the money to medical __________ ( 研究).
I think reading ___________ (大声)is a good way to practice pronunciation.
We should ____________ ( 当作) our problems as challenges. Don’t complain about them.
Every afternoon , some students feel ____________ (不活跃的). They are so tired.
The child is old enough to take care of ____________( 自己) . She is 15 now.