Only after I read the book _______ why she devoted all her life to medical work forChinese women and children.
Not until _______ 18 years old _______ a right to vote.
--Who is the person talking with you just now? -- Well, if you ______ know, his name is David.
Alice, _______ university teacher from Australia, teaches me ______ English in her spare time.
It is morning _____ we have four classes, not afternoon.
In the reading room, we found her _____ at a desk, with her attention ______ on a book.