请教几道语法题~谢

bbxiaos

改错：.(不知道红色的错在哪里，怎么改？？？)

1.The pear tree has simple, oval leaves that are smoother and shinier than them of the apple.

2.The eighteenth century witnessed the emergence of North American ports, particular Boston, New York, and Philadephia, as major commercial centers within the British empire.

3.By 1830 the glass industry in the United States had become too well established that the country no longer needed to depend on imported glass.

4.The first city in the United States that put into effect major plan for the the clustering of government buildings was Washington DC.

Thx~！！

xizzhu

以下是引用bbxiaos在2006-4-8 0:14:00的发言：

改错：.(不知道红色的错在哪里，怎么改？？？)

1.The pear tree has simple, oval leaves that are smoother and shinier than those of the apple.  those = leaves

2.The eighteenth century witnessed the emergence of North American ports, (which are) particularly Boston, New York, and Philadephia, as major commercial centers within the British empire.

3.By 1830 the glass industry in the United States had become so well established that the country no longer needed to depend on imported glass.   "so....that"

4.The first city in the United States that put into effect major plans for the the clustering of government buildings was Washington DC.

Thx~！！

bbxiaos

Thx!!!