现在有果汁含量为40%的饮料600ml，要把它变成果汁含量为25%的饮料，需要加

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Hi, Tim: 

       Thank you for your invitation to visit your school next week, I am sorry I can't come. I'm not free next week. On Monday, I am having a piano lesson from 8:00 to 10:00 in the morning, and I have to study for

the math test in the evening. On Tuesday, I am meeting a friend from my hometown at the train station. On Wednesday, I'm playing football with my friends. I have to look after my sick grandpa on Thursday. On

Friday, I'm helping one of my classmates to study English. I'm really busy the whole week.

                                                                                                                                                  Yours,

                                                                                                                                                   Frank

1. Why can't Frank visit Tim's school next week?

A. Because he has a piano lesson.      

B. Because he is busy.

C. Because he is ill.                  

D. Because he is playing football with his friends.

2. How long is Frank having a piano lesson on Monday?

A. One hour.      

B. At 8:00 o'clock.    

C. Two hours.    

D. At 10:00 o'clock.

3. Where is Frank meeting his friend on Tuesday?

A. At the train station.  

B. From his hometown.  

C. At a bus station.  

D. At school.

4. Who is Frank going to look after next week?

A. His friend.          

B. His classmates.    

C. His grandma.  

D. His grandfather.

奥氏体是（）

A.碳溶解在γ-铁中

B.碳溶解在α-铁中

C.渗碳体溶解在γ-铁中

D.过饱和的α固溶体

血海主治不包括（）.

A.月经不调

B.水肿

C.瘾疹

D.湿疹

E.丹毒

正确鼠药投放方法是（）。

A.抛散在室内外明亮处

B.成堆放置在墙角、墙边隐蔽处

正常行使速度是根据什么来确定的？