确保切方渠段不滑坡的关键措施是（）。
A、减小渠道断面尺寸
B、增大渠道断面尺寸
C、保持排水畅通
D、暂停使用
参考答案：C
Look and judge. 看图，判断正(T)误(F)。
1.This country is Canada. The capital city of Canada is Canberra. They speak English. ( )
2.This country is the U. K. The capital city of the U. K. is London. ( )
3.This is Tian'anmen Square. It is in Beijing. ( )
4.This is south. South points down. ( )
5.In this country, there are beautiful beaches. The capital city is Ottawa. ( )
This country is Canada. The capital city of Canada is Canberra. They speak English. ( ) 
This country is the U. K. The capital city of the U. K. is London. ( ) 
This is Tian'anmen Square. It is in Beijing. ( ) 
This is south. South points down. ( ) 
In this country, there are beautiful beaches. The capital city is Ottawa. ( )