The meeting was put off because we ________ a meeting without John.

Many _______ of years later, the first extremely small plants began to appear on the surface of the water.

It is a great       for any man to be able to talk or hear, neither ignorantly nor ridiculously, upon any subject.

While income worry is _______ rather common problem of the aged, loneliness is another problem that _______ aged parents may face.

 —Good morning.I've got an appointment with Miss Smith in the Personnel Department.—Ah，good morning.You ________ be Mrs.Peters.(2010·北京)