Indonesian students sometimes struggle because they lack of critical thinking skills.
It’s true that ‘lack’ collocates strongly with ‘of’, but only when ‘lack’ is a noun. When ‘lack’ is a verb, there is no ‘of’!
- Indonesian students sometimes struggle because they lack critical thinking skills.
If you really want to use lack of then treat ‘lack’ as a noun:
- A lack of critical thinking skills sometimes causes Indonesian students to struggle.
Once again, in lack of, ‘lack’ is a noun, not a verb!
Some students demonstrate a understanding when it comes to the word ‘lack’. Perhaps they the ability to identify the difference between noun and verb forms? Or perhaps there is a examples of ‘lack’ in the texts that they read? Either way there is a definite ‘lack’ as a verb in their writing!