has been interested in space since childhood

is the author of some famous books

started to write books about the universe in 1988

has been recently keen on studying space

isn’t it

hadn’t it

didn’t it

wasn’t it

before Tet holiday approached

after Tet holiday approached

as Tet holiday approaches

while Tet holiday was approaching

manner

degree

custom

habit

made

held

went

took

terrible

enjoyable

normal

expensive

become

independent

privacy

reach

I have visited Nha Trang many times before.

The last time I visited Nha Trang was last year.

I haven’t visited Nha Trang for many years.

I have never visited Nha Trang before.

where

that

what

whose

lain

laying

laid

to lie