$\text{31.}$ learning

$\text{→}$ started/ began + V-ing

$\text{32.}$ surprised

$\text{→}$ was + adj

$\text{33.}$ vocabulary

$\text{→}$ lots of + N

$\text{34.}$ with 

$\text{→}$ stay with sb: ở với ai

$\text{35.}$ improved: cải thiện

II.

$\text{36.}$ A

$\text{37.}$ B

$\text{→}$ During 1510s fewer than two million people spoke English.

$\text{38.}$ A

$\text{→}$ Today, about 400 million people speak English as their native language. Most of them live in Australia...

$\text{39.}$ C

$\text{→}$ Most of them live in Australia, Canada, the UK, Ireland, New Zealand, South Africa, and the US.

$\text{40.}$ D

$\text{→}$ chiefly = mainly: chủ yếu

III.

$\text{41.}$ C

$\text{→}$ ago chia QKD

$\text{42.}$ B

$\text{→}$ different + from: khác với

$\text{43.}$ A

$\text{→}$ customer: khách hàng

$\text{44.}$ B

$\text{→}$ for + example: ví dụ

$\text{45.}$ A

$\text{→}$ customer chỉ người dùng và sau nó ko có mệnh đề nên dùng who