问题
单项选择题
添加润滑剂可以改善塑料熔融时流动（）。
A.温度；
B.速度；
C.粘度；
D.密度。
答案
参考答案：C
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添加润滑剂可以改善塑料熔融时流动（）。
A.温度；
B.速度；
C.粘度；
D.密度。
参考答案：C
| 完形填空. | ||||
| In many parts of China, spring is usually very 1 . It usually comes 2 February 3 March. Summer is very 4 . It lasts (持续) from May to July. The hottest (最热的) month is July. Autumn 5 in August, and goes on to October. The weather can be quite 6 in autumn. Winter lasts from November to January, and is very 7 . You 8 to wear 9 warm clothes. The best time to 10 to China is in spring or autumn. | ||||
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