18. They have produced (   ) they did last year. 

• A、 twice as much grain as

• B、 twice more grain as

• C、twice as many grain as

• D、 as twice many grain as

52 (   ).

39. The Chinese use "Go slowly"in their partings so as to (   ). 

• A、slow down the guests

• B、ask the guests to take care

• C、wish the guests a happy journey

• D、warn the guests of danger on their way home