The phrase "a pretty slow" is not correct in standard written English.
It can be used in informal contexts, but it typically requires a noun to follow, such as "a pretty slow process" or "a pretty slow day."
Example: "It was a pretty slow afternoon at the café, with hardly any customers coming in."
Alternatives: "quite slow" or "rather slow".
I'm a pretty slow reader and read it in about ten days.
"It's a pretty slow process, to raise the money country by country.
"If you have a surface with high friction and high bounce, you've got a pretty slow court," Miller said.
Rumors of a slowdown first began to circulate in the Capitol on Thursday, a pretty slow day anyway because the legislators have left for the weekend.
"The way Smith came out on a pretty slow wicket and hit some great shots to take the game away from us was amazing.
Charles O. Rossotti, the I.R.S. commissioner, said early disclosure of tax shelters "will give us better information to focus our resources" and will speed up "a pretty slow and indirect process" of hunting for abusive shelters one at a time.
It's a pretty slow-moving storm, so you can expect it to hit the area either overnight or by dawn at the latest.
A viewer new to baseball might have seen this flurry of odd and beautiful action as the high-water mark of what, being a National League game, was an otherwise pretty slow and staid affair.
The first thing is the transformation into a vampire is pretty slow to so start acting like a vampire bit by bit.
Brown does a bit of heavy breathing himself on "Royalty," most memorably in "Make Love," a humid, rather pretty slow jam with unexpected echoes of Prince and D'Angelo.
Destroy Erase Improve was like exploring the dynamics of the band, Chaosphere was exploring the aggressiveness, the all-out side, and Nothing is more of a sinister, dark, pretty slow album, actually.
