《列车干线绝缘测试值表》中规定，湿度≤60%时，DC600V供电运用列车线间绝缘须≥

读短文判断(√)错(×)。

                                                             Sam's Diary

                                                                                                      Tuesday, Cloudy

     Today I had two hamburgers at lunch. I like hamburgers very much. I wanted to have another one.

But Mum didn't want me to eat too much. She doesn't like hamburgers. She drank some juice. Tomorrow

is Dad's birthday. Mum is going to make a cake for him. I'm going to eat lots of delicious food. I wish Dad

a happy birthday!

( ) 1. Sam ate two hamburgers today.

( ) 2. Sam's Mum likes hamburgers very much.

(     ) 3. Sam's Mum drank some juice at lunch.

( ) 4. Sam's Mum is going to make a cake for Sam.

( ) 5. Murn is going to have a happy birthday.

方程9^x－6·3^x－7＝0的解是           ．

空气细菌学评价指标是

A．细菌总数、链球菌总数
B．细菌总数、金黄色葡萄球菌
C．细菌总数、绿色链球菌
D．细菌总数、溶血性链球菌
E．细菌总数、流感病毒

甲厂向乙厂发出要约，推销磁粉。乙厂给甲厂答复：同意甲提出的其他条件，但磁粉价格须每吨降低150元。乙厂的这一答复属于承诺。 ( )