"She advises me to read books whenever I feel sad."

Translation: Cô ấy khuyên tôi nên đọc sách mỗi khi tôi thấy buồn.

[KirynSilverwing]

Mine marked my answer correct but had "another translation" that was identical to what I put down except for an extra space between two of the words (which I could not have added because this was a word selection exercise) .

[smirki1]

Why can't I use "khi nào" for "whenever" as Duo taught us in previous lessons?

[KflHZ]

Is nên necessary?

[cressfallen]

Is this the same thấy we use for see? So it can mean both see or feel?

[TehVanarch]

Thấy here is short for "cảm thấy".

[StewartMM]

Why not simply buồn? Feeling sad and being sad...is there really any difference??

[vngdhuyen]

no. and it's accepted.

[leaderdmd]

Why isn't cảm thấy accepted?

[vngdhuyen]

do you mind providing the full sentence you gave because many answers with "cảm thấy" are already accepted. over 475 different sentences are accepted for this sentence alone...

[leaderdmd]

Thank you for checking, Có ấy khuyên tôi nên đọc sách mới khi tôi cảm thấy buồn.

Mỹ original answer looks just like 482.

[StewartMM]

it's accepted now.

[StewartMM]

Why was 'trong khi' not accepted instead of 'mỗi khi'?

[Cathy224317]

I think "trong khi" means "while"

[StewartMM]

And why is ''các quyển sạch' marked worng?

[Cathy224317]

I think it's because the sentence refers to books in general, which doesn't require a classifier, whereas your answer, with the classifier, refers to specific books, or 'the books'. That's the way I understand it, although I may be wrong.