Câu 1 : Tính khối lượng của : 

a, 0,5 mol H₂SO₄   

b, 2 mol NaOH 

c, 0,2 mol Al₂(SO₄)₃                                                                                               

1 : " will you be visiting the Taj Mahl when you go to India? " he asked Elizabeth 

--- he asked ....

2: " i think you should try the chicken Marengo" said the waiter 

--- the waiter recommended ......

3: this is the most delicious cake i have ever tasted 

--- i have ... 

4 : just after solving one problem , i was faced with another 

--- Scarcely ....

5: without his help , we would all have been in worse trouble 

--- hadit ....

6: no students in my class can speak English as fluently as she does

--- she speaks .... 

7 : my father started to read that book two weeks ago .  he's still readingit

--- my father has ....

8 : " i don't want to be criticized by non - professionals", said the filmstar 

--- the film star objected  ...

1: he was very sorry that he didn't see Andrey on trip to London                                 --- he greatly regretted ....                                                                                     2: it's thought that hte accident was caused by human error                                     ---the accident is ......