Especially if you received a pretest RQ I would lean towards NOT sending the originals but instead sending photocopies and keeping the originals to bring along to future tests or interviews. There have been a few reports of the CIC losing or misplacing RQ responses (i.e. contacting RQ recipients a year after they sent their RQ response with a threatening letter telling them that they never sent in their documents and if they don't do so ASAP, their application with be deemed abandoned and closed). Side note: This is why it's important to keep your tracking number and proof of signature for RQ responses.
Back to the subject at hand: Sending the original & certified translations carries some risk. The translations are replaceable, but it's a question of whether the risk of the expense and hassle of replacement would be worth the benefit of sending the CIC office the original (even though they do not explicitly request it).
Ultimately, like so many RQ-related subjects, it is a grey area, so it's up to you to decide what approach you are most comfortable with.
