根据所给单词的首字母, 完成下列句子 （共10小题；每小题1分，满分10分）
The boy felt u________ because he didn’t do well in the exam.
Don’t let your dog l_______ if there are any sheep around.
Before the c_________ went up, the dancers took their places on the stage.
The hotline helps many t__________ who are growing up.
After a few days of fever, he began to r_________.
Chinese is the o_________ language of China.
I will have to increase my ___________(词汇量)
He speaks English f________, for he has stayed in England for quite a long time.
It took four years to plan the _____________（航行）
The police soon established his true i__________ and he was quickly found.