問答題下面是某高中教師在新授環(huán)節(jié)之后設(shè)計的課堂練習(xí)。
Join the pairs of sentences using attributive clauses（restrictive or non-restrictive）.
Here are the farmers. They discovered the underground city last month.
Hangzhou is a famous city in China. Many people come to buy tea in that city.
She got so angry. I don＇t know the reason.
The old man saw some Germans taking apart the Amber room and removing it. You are talking to an old man.
The woman remembered the day. She saw Nazis burying something near her home.
St Petersburg is a very beautiful city. It was once called leningrad.
I remember the soldier he told me not to tell an yone what i had seen.
The soldiers moved the boxes to a mine. They wanted to hide them.
Xi an is one of the few cities with city walls. Its walls remain as good as before.
Shanxi Province is a place with many cultural relics. They are well looked after.
根據(jù)上面所給的信息，從下列三個方面作答
（1）分析此練習(xí)題的目的。
（2）分析此練習(xí)題的弊端。
（3）教師在安排學(xué)生課上練習(xí)題時的注意事項有哪些？