[General] can we vs we can

[kuykuy]

Hi, I'm confused about these two sentences:

Only on the weekends we can have dinner together.

Only on the weekends can we have dinner together.

The second one sounds right to me, but I don't know the grammatical explanation.

 

[jutfrank]

Your sense is good, kuykuy. The second sentence is the correct one.

The beginning phrase Only on the weekends means that the following subject (we) and auxiliary (can) are inverted.

 

[Rover_KE]

Welcome to the forum, kuykuy.

 

[PaulMatthews]

[1] *Only on the weekends we can have dinner together.
[2] Only on the weekends can we have dinner together.

You are right.

Your second example correctly has subject-auxiliary inversion. This occurs in declarative clauses only when certain types of element are put in front position. Negatives are one very obvious type of element that trigger subject-auxiliary inversion when fronted:

"Never had I seen such chaos".
"At no stage were they in danger".

"Only" is not negative, but it is semantically close to a negative, in that "Only John liked it", for example, entails "No one other than John liked it".

The inversion is also found with some items that are not similar to negatives:

"John enjoyed it and so did Robert".