proofreading!! help!

It should be:

children should master the basics first. (not firstly)

first: here means before doing anything

Firstly is an adverb for giving reasons.

for example: Firstly, ....
Secondly, ....

firstly should be changed into first.

competent --> competitive 係adj

.....係你寫的嗎 or bk ge....??

其實唔係太明後句想講d 咩..........