French language Q&A Forum

Bonjour ! Can you explain me how to use tiret (-) in writing numbers ? Merci ! 

Merci beaucoup!

Cet exercise était amusant et m'a fait rire.  Merci!  

In the above sentence, why is the correct answer "moins d'énergie que" and not "moins d'énergie que de"?  I added the "de" based on this rule: "When expressing there are more/fewer/as many-much [thing/s] than/as [other thing/s], you need to add de after que".  

Can puis be used instead of ensuite. As this was not presented as a correct alternative.

mais 'puis' je me suis réveillé, et ce n'était qu'un rêve !

Question today was "Un jour, on _____ sur Mars."  In a previous   test, "On a ______ opinion."  The previous answer was "On a notre opinion," but today's test was said to be "On ira sur Mars."  How is one to know if the "on" refers to a singular person (on ira) or to several individuals (On a notre opinion)?  It's a bit confusing.  Please clarify.  Thanks.

This exercise only accepts "Je ne sais pas quoi dire" as translation, but I just wanted to confirm that "Je ne sais que dire" is also correct, or is there some difference in meaning between the two that excludes the latter?

Selon Grevisse, on n'est pas obligé d'accorder "on" au féminin ou au pluriel quand le sujet est bien défini et féminin ou pluriel (voire les deux).