"A is not as ~ as B ."
Used to express that while A and B are about the same as ~, when compared, X is of a lower degree than Y.
The negative form is alway used.
Tom is not as tall as James.
English is not as difficult as Japanese.
I think a computer is not as convenient as a smart phone.
Japanese summer is not as hot as my country’s.
It’s not not as busy today as it was yesterday
This time’s test is not as difficult as last time