已知i是虚数单位，若a+3ii=b+i(a，b∈R)，则ab的值为______．

短文改错（共10小题；每小题1分，满分10分）

例如: It was very nice to get your invitation to spend ∧ weekend with you. Luckily I was the                        am  completely free then, so I’ll to say “yes”. I’ll arrive in Bristol at around 8 p.m. in Friday evening. on

 
Sports and games are very useful for character training. In their lessons at the school, boys and girls may learn about such virtues like unselfishness, courage, discipline and love of one’s country. So what is learned in books cannot have the same deep effect on child’s character as what is learned by experience. As most of the pupils’ time is spent in classes study lessons, the ordinary day school can’t give many practical training for their lives in the future. So it is how the pupils do in the spare time that really prepare them to take their places in society as citizens when they grow up. Unless each of them learns to work for his team, and not for himself on the football field, he will later find it naturally to work for the good of his country instead only for his own benefit.