Collective nouns, like "La clase", take singular verbs in Spanish, so it would theoretically be "se duerme" and NOT "se duermen". However, the sentence in the question does not make much sense. If the sentence was supposed to be "The class falls asleep because the teaching is uninteresting", it would be "La clase se duerme porque el enseñamiento no es interesante."
Se duermen
Vuelva al coche y dormirse.
There is a customary Spanish question that translates, "How did you 'dawn'?" which means the same as the object question. When it's said politely, it's said, "¿Cómo amaneció? When said informally, it's said, "¿Cómo amaneciste?"
Present indicative conjugation of dormir: duermo, duermes, duerme, dormimos, dormΓs, duermen
There are no Spanish words with double s's. The only occurrence of an "ss" would involve onopatopoeia (like the simulation of a snake's hissing in literature) or in names borrowed from other languages, such as from French or Italian.
(i) The 'se' ending at the end of Spanish verbs indicates the Reflexive form, which corresponds basically to the English use of 'to....(one)self'. One way of translating the second example below (bañarse/ducharse) is 'to bathe oneself/to shower oneself'. (ii) In Spanish, however, the form is also used to indicate the Passive form, corresponding to 'to be....ed', as in the two final examples (decirse/escribirse). (iii) One additional complication is shown by the third example (irse), which doesn't have an English equivalent unless you treat 'irse' as meaning 'to go away': 'ir' meaning 'to go', and 'se' adding the 'away' element. The verb 'marchar' (walk) works in a similar way, 'marcharse' meaning 'to walk away'. # dormirse --- to fall asleep. bañarse / ducharse --- to take a shower. irse ---- to go. decirse ---- to be said escribirse ---- to be written. ... ... ... Actually, there isn't any simple rule. The two languages do not have total one-to-one correspondence. *I recommend you to use an excellent Spanish- English dictionary.