The phrase "are sometimes ugly" is correct and usable in written English.
It can be used to describe something that is not always aesthetically pleasing or has an unpleasant appearance at times.
Example: "The designs of some modern buildings are sometimes ugly, contrasting sharply with the classic architecture of the city."
Alternatives: "can occasionally be unattractive" or "are not always beautiful."
In the fourth quarter, he was 10 of 19 for 137 yards and 2 touchdowns, and there is no way coaches can ignore his ability to steer a team to victory even if the road there is sometimes ugly.
"What we've shown this season," City's matchwinner said, "no matter if it's Champions League, Premier League, cup games, we've got the mentality that we want to win and even if it's sometimes ugly, we just try to make sure we get the win".
The result is sometimes beautiful, sometimes ugly, but never less than utterly extraordinary.
The Bristol-based duo cites early garage, grime, and the one man genre known as Burial as their main influences, which explains why their music is sometimes punchy, sometimes ugly, sometimes pretty, and often packing more low end than your usual house groove.
He also tended to lean into each note with his voice, swelling into a straight, hard sound that was sometimes downright ugly.
Now small cameras — the cycling equivalent of the black box on an airplane — are becoming an intermediary in the relationship, providing high-tech evidence in what is sometimes an ugly contest between people who ride the roads on two wheels and those who use four.
Sondheim pries into the corners of our own self-interest and ruffles our careful complacency to get at something real that is sometimes as ugly as the smell of liquor on a drunk's breath: the troublesome nature of love and intimacy, and the way society is formed less by choice than by convenience.
The primarily nocturnal pyjama shark isn't very bright and is sometimes is considered ugly, on the other hand it spends most of the day lying motionless, hidden in a cave or crevice or among vegetation.
