I think it is usual to use that as a conjunction in these examples.
See the definition that:
- a subordinating conjunction used to introduce:
So I would write thesethem as follows:
We recommend that you book your flight early.
He recommends that you read the book before watching the movie.
I recommend that you go there.
I suggest that you go to the sport center.
SeeAlso check the definition recommend and you can see this form:
- to advise; counsel; suggest ⇒ "to recommend that something be done"