`11,` The bigger the apartment is, the higher the rent is.

`12,` The sooner we set off, the sooner we arrive.

`13,` The better the joke is, the louder the laughter is.

`14,` The fatter she gets, the more tired she feels.

`15,` The older he gets, the less he wants to travel.

`-.-.-.-.-.-` 

${\text{Giải thích: }}$

`+` So sánh kép:

`-` The `+` so sánh hơn `+` S `+` V ..., the `+` so sánh hơn `+` S `+` V..

(`+`) Cấu trúc so sánh hơn `-` ngắn (giữa 2 người/vật):

`->` S `+` V/tobe + adj/adv `+` -er `+` than `+` O...

(`+`) Cấu trúc so sánh hơn `-` dài (giữa 2 người/vật):

`->` S `+` tobe/V + more + adj/adv `+` than `+` O..

.