Translation:I know how to use a computer. In addition, I am an accountant.
Without a classifier, is it singular or plural? As far as I recall, some sentences here do not have a classifier and refer to plural.
This sentence does not focus on a particular object (in this case, computer) so classifier is not needed and it can either mean singular or plural. It's also true that without classifiers, usually the word would be plural.
Yet, it's still marked wrong if you write computers instead of a computer.
Where is the "mot"??? Thus, "I know how to use THE computer..." should definitely be accepted!!!
"I know how to use computers" should be accepted. The sentence is talking about knowing how to use computers in general. If the object of the sentence was "the computer", it should be "Tôi biết dùng cái máy tính". If it was "a computer, it would be "Tôi biết dùng một máy tính".
Also, I think "also" should be interchangeable with "in addition", no?
"Computers"--generic plural--is also what we've been taught. But once again they break their own rules.