问题 选择题

现将10gA和足量B混合加热,A和B发生化学反应,10gA完全反应后生成8gC和4gD,则参加反应的A和B的质量比是(  )

A.1:1

B.2:1

C.4:1

D.5:1

答案

10gA完全反应后生成8gC和4gD,由质量守恒定律可知,参加反应的B的质量为2g,故参加反应的A和B的质量比是10g:2g=5:1.

故选D.

完形填空

Many Chinese students don’t pay much attention to spoken English at school. They think it necessary to practice   36  English in class, but not   37  class. Here is a story to show you   38  important it is to speak the English language freely in everyday life.

A foreigner once   39  hungry and went into a restaurant in London. He sat down at a table. When the waiter came, he   40  his mouth, put his fingers into it and took them out again in order to   41  that he wanted something   42  because he could not speak English. The waiter soon   43  him a cup of tea. The man shook his head. The waiter then took   44  the tea and gave him a cup of coffee. Still the man didn’t   45  what he wanted. He tried again and again, but he wasn’t able to make the waiter   46  him. Finally   47  man came in. He spoke English   48  and fluently. After a few minutes, there was a large plate of meat and vegetables on the table in front of   49  .

So you see a man can go hungry if he   50  master(掌握)a foreign language.

小题1:A. speak                       B. speaking                 C. to speak

小题2: A. outsider                   B. out                      C. out of

小题3: A. how                        B. how an                   C. what an

小题4: A. get                        B. gets                     C. got

小题5:A. open                       B. opened                   C. opens

小题6: A. express                        B. expressed                    C. expressing

小题7:A. eats                        B. eating                       C. to eat

小题8:A. took                        B. brought                  C. bought

小题9:A. away                        B. out of                       C. down

小题10:A. make                        B. give                     C. get

小题11: A. understand                 B. understood                   C. be understood

小题12:A. other                       B. the other                    C. another

小题13:A. clean                       B. clear                        C. clearly

小题14:A. he                          B. him                      C. his

小题15:A. doesn’t                        B. won’t                       C. isn’t

选择题