中暑痉挛区别于其他各型中暑的主要特征是
A.头痛
B.恶心、呕吐
C.惊厥
D.阵发性肌肉痉挛疼痛
E.全身疲乏
参考答案:D
To understand the grammar of the sentence,you must break it ________ into parts.
A.up
B.down
C.off
D.out
作物产量与产量构成因素间的关系如何?