I don‘t know how much I spend （ ）all kinds of books every year.｛buyWhat do you think （ ）the most important event in the world last years?｛beThis year alone,I （ ）more than fifty English compositions,but none of them （ ）successful

Question

I don‘t know how much I spend （ ）all kinds of books every year.｛buy
What do you think （ ）the most important event in the world last years?｛be
This year alone,I （ ）more than fifty English compositions,but none of them （ ）successfully .｛write write
用所给词的适当形式填空

Answer 1

本来没分有人答的问题我是不高兴答的,不过我觉得上面三位的答案都稍微有点问题,所以写一下我认为的答案,望高人指点一下是否正确.
1,in buying 理由：speng on sth/ in doing sth
2,was ,理由：这里单三毫无疑问,而时态我觉得“do you think ”是个干扰,去掉看就明显是过去时.
3,have written ,was written 理由：“this year along” 明显是和现在有关的过去,用现在完成； 后半句主语“none of them”先判断为单数,然后them指代的书肯定是被写,最后,从前半句中得知这些书已经被写,所以是过去时.
现在初三的英语就已经这么.我国真是培养人才的地方