What happened to the young trees we planted?—The treeswell, but I didn’t water them.

With the advances of technology, plastics have taken the place of many ________materials.[ ]

China is one of _______countries in the world.

Last night Mr. Crook didn’t come back atthe usual time.______，he met some friends andstayed out until midnight.

与字母M含有相同的元音音素的一组字母是 。