Becoming worse vs. getting worse

[reiner]

English Grammar Error, Intermediate level

ESL/EFL Test #8 "Tenses", question 4

The weather is becoming worst every day and we are going on holiday on Tuesday.

(a) is becoming
(b) worst
(c) are going
(d) on

English Grammar Error, Intermediate level

ESL/EFL Test #8 "Tenses", answer 4

The weather is becoming worse every day and we are going on holiday on Tuesday.

Correct entry: worse
The error was: (b) worst

You have not found the error.
The weather is getting worst every day and we are going on holiday on Tuesday.
_________________________

I can see that "worst" is clearly the mistake in this sentence, but wouldn't "is getting" sound more natural in this particular sentence?

Maybe wrong

[Mister Micawber]

.
Perhaps more casual, but certainly not more natural.
.
_________________
Canadian-American native speaker
who teaches English for a living at Mister Micawber's
ESL cafe: Interview with Mr. Micawber