如果有连接词"and "的话,就填them.
注意中间有","隔开并且没有and连接
They have planted many trees,one third of which are pine trees.=
They have planted many trees and one third of them are pine trees.
注意区别.
如果有连接词"and "的话,就填them.
注意中间有","隔开并且没有and连接
They have planted many trees,one third of which are pine trees.=
They have planted many trees and one third of them are pine trees.
注意区别.