重症肌无力的临床特征为（）
A.波动性肌无力
B.多伴肌萎缩
C.晨轻暮重
D.活动后加重，休息后减轻
E.骨骼肌易疲劳
参考答案：A, C, D, E
根据所给单词和句子意思，写出正确的单词形式。
1. Boys and girls, Help ________(you).
2. I have many personal ________.(strong)
3. He introduces ________(he) to us.
4. My friends are _________(Germany).
5. I like to play ping-pong. I am one of the best ________(play) in the school.
地球自形成以来可划分为五个代，从古至今第三个代是（）
A、太古代
B、中生代
C、元古代
D、古生代
e) to us.