正级绝缘的电动机，其绝缘材料的耐热极限温度为（）℃。
A.105
B.120
C.130
D.155
参考答案：B
请写出下列单词划线部分的音标
1. thunder ________ 2. swap _________ 3. command ________ 4. prefer ________
5. stubborn _______
—Can you tell me this morning?
—Sorry, I've no idea.[ ]
A. why didn't Daming come to school
B. why Daming didn't come to school
C. why doesn't Daming come to school
D. why Daming doesn't come to school
