wait...well ...
1.如果用would ,应说I wonder why you would think so!
2..
My cat is really fat.
You ( ) have given her so much food.
B wouldn’t如果放进去,整句意思为"你不会给它那么多食物的(言外之意是别人下的毒手)" C couldn’t 你不可能给它那么多食物的(同上)
3.这句话的关键是but he meant no harm .意思是"他当时认为不会伤害你",说明事情 已经 发生!现在后悔当然用A have told!
Oh!...so tired...go to sleep.