代词:人称、物主、反/自身、指示、相互、疑问、不定代词As they were classmates, ________ was no wonder that they should do the work in the same way
It’s wise to forget things which aren't worth ______.
With the fast development of computer and Internet technologies, traditional printed books ______ by the growing popularity of online reading of e-books.
In many people’s opinion, that company, though relatively small, is pleasant ______.
The computer system _____suddenly while he was surfing the Internet.
It is usually warm in my hometown in March, but it _____ be rather cold sometime.