My name is Mary Green. I live in a new house with my parents. There is a beautiful and a small room for me. I like it very much.

Now let me tell you something about my new house. My new house is on a busy street. There is a big, new and clean park across from my house. I can see the flowers in it from my room. We often take a walk in the park after dinner every evening. There is a big supermarket near my house. It is between a hospital and a cinema. We can buy fruits, vegetables and food in the supermarket. They are good but cheap. My school is near my house. So I always go to school on foot. I like my new house. Do you like it?

小题1:How is the park?

A．old

B．big

C．dirty

D．small小题2:Where is the cinema?

A．It is across from my house.

B．It's between a bank and a supermarket.

C．It's beside a park.

D．It's beside a supermarket.小题3:We can't buy _______in the shopping mall.

A．fruits

B．vegetables

C．food

D．flowers小题4:Which of the following is TRUE?

A．I walk to school from Monday to Friday.

B．There is no cinema near my house.

C．The street is very quiet.

D．My first name is Green.

把V L含有MgS0₄和K₂S0₄的混合溶液分成两等份，一份加入含a mol NaOH的溶液，恰好使镁离子完全沉淀为氢氧化镁;另一份加入含b mol BaCl₂的溶液，恰好使硫酸根离子完全沉淀为硫酸钡。则原混合溶液中钾离子的浓度为（   ）

A．mol·L^-1

B．mol·L^-1

C．mol·L^-1

D．mol·L^-1