I want to buy a blue jacket to ________my blue trousers.

________ children whose parents had died in the earthquake________ sent to live with families in other cities.

(2009·陕西高考)I still remember________to the Famen Temple and what I saw there.

At last they got the letter they____________．

Carbon dioxide, which makes a ______ between us and the sun, prevents heat from getting out of the atmosphere easily, so the earth is becoming warmer.