summit
The road to social mobility … it is an agonisingly steep path up a
mountain whose summit is never quite in view。
peak
If a person finds getting up early a problem, most probably he is
at his peak in the afternoon or evening.
vague
Researchers … found many too vague or too misleading to meet
ISO standards.
doubtful
The author is doubtful about the necessity of keeping H-bombs
at home for safety.
dim
The elderly man suggests having a brighter bulb some where
because this light is too dim for us to read by.
sour
A: Geez! The milk gets sour. It makes refrigerator smelly.
B: Throw it away.
