1.expand "展开,扩大", 指尺寸的增加、范围和体积的扩大.侧重"膨胀"。

His ambition expands.

As children grow older they expand their interestes and become more confident.

2.extend "伸出,延伸", 指空间范围的扩大、长度、宽度的朝外延伸、时间的延长.侧重“时间和空间的延伸”.

The road outside the village extends to the south.

The rainy weather extended to November.

3. spread "伸开,传播", 指向四面八方扩大传播的范围,侧重于传播和散布.

The rumour spreads quickly all over the town.

H1N1 spread fast all over the world in one year.

4. stretch "伸展,拉长",指由曲变直、由短变长的伸展，不是加长。侧重“形状的变化”.

He strethed out after a long time's work.

The cat stretched out in front of the fire.