We need to be more ____ ____ the needs of young students.

The king had many sons, whose ages ____  ____ three to thirty.

They are friends, so it won’t hurt for them to ___    　　　　  _____ each other.

As was ____  ____, life on our planet began in the deep blue sea.

They give love and care to raise their children and educate them to be responsible ________ (公民).

________ (分离) between his friends made him sad.

Slums (贫民窟) are often the ________ (滋生地) of disease.

He is very ________ (敏感) about his ugly appearance.

Pakistan's ________ (关系) with India has changed dramatically.

Sound travels through the ________ (媒介) of air.