6. He was able to speak two languages when he was young.

 - be able to + Vo: có thể làm gì...

`*` Dịch: Khi còn bé, anh ta đã có thể nói 2 thứ tiếng.

7. He is keen on reading books on the internet.

 - be keen on/interested in/fond of + V-ing: thích làm gì....

8. Why don't we go to school by bike?

 - How about, What about + V-ing/ Let's + Vo/ Why don't we + Vo: Nhũng câu nói về gợi ý một hành động gì...

9. Liz helps her mom look after her brother.

 - take care of (cụm động từ): chăm sóc = look after (cụm động từ).

`6.` He was be able to speak two languages when he was young.

`->` be able to + Vinf : có thể làm gì 

`7.` He is fond of reading books on the internet.

`->` like = be fond of + Ving : thích làm gì

`8.` Why don't we go to school by bike ?

`->` How about + Ving = Why don't we + Vinf : câu gợi ý về một việc gì đó 

`9.` Liz helps her mom looks after her brother.

`->` take care of = look after : chăm sóc