They have given us a lot of valuable ________.
A. information
B. informations
C. informing
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He did ________for his examination.
A. a little prepare
B. little preparation
C. little preparations
In modern age, electronics ________ very fast.
A. have been develop
B. has been developing
C. had been developing
Hatred and misunderstanding between communities ________ which we can no longer afford.
A. are lazy and primitive feelings
B. is lazy and primitive feeling
C. are lazy and primitive feeling
使用高斯模型的假设条件有哪些？
A. 污染物浓度在y、z风向上分布为正态分布
B. 全部高度风速均匀稳定
C. 源强是连续均匀稳定的
D. 扩散中污染物是守恒的（不考虑转化）
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