Question

きとりろく

誤字訂正についての問題です。

(1)Helen was more (carefully) (than)
(her hasband)(when driving) a car.
答え carefully→careful

(2)(A friend) of (me) (told) me (not to smoke) so much.
答えme→mine

(3)He comes to school (earlier) than (any) other (classmates) (in) his class.
答えme→mine

(4)(Although) she didn't have (enough) money, she (bought) a lot of furnitures.
答えfurnitures→furniture

どうしてこうなるのかがわかりません。
教えてください。

また、このような問題に使える知識も教えていただけると助かります。