The phrase "are sometimes suspicious" is correct and usable in written English.
It can be used when discussing the behavior or attitudes of individuals or groups that may exhibit doubt or mistrust in certain situations.
Example: "Some people are sometimes suspicious of new technology, fearing it may replace their jobs."
Alternatives: "can be wary" or "may have doubts".
Two thirds of Vietnam's Protestants are ethnic minorities, and many live in remote areas where neighbours are sometimes suspicious of the converts.
So, rather than tiptoe around it, Swain, a mother of two black boys, also acknowledged that black people are sometimes suspicious of black males.
During his father's White House years, W. was sometimes suspicious of Ms. Tutwiler, fearing she might be leaking information that made Mr. Baker look better than President Bush; but, grateful for the work of the pair in Florida, W. has put that skepticism behind him.
On other topics, however, he is sometimes suspicious about whether a position handed down as Plato's is in fact Plato's.
Wild dingoes, though bold and suspicious, can be tamed, and they are sometimes captured and tamed by Aborigines.
The narrators were sometimes bitter or suspicious, but mostly friendly, almost invariably courteous, and occasionally, like Parapa, very funny.
He was curious, sometimes suspicious, a voracious reader, and a sonic explorer.
However, FNAs were sometimes performed on multiple nodules in one patient because of multiple suspicious US features, physician's or patient's request.
Sometimes suspicious behavior is a normal thing that a law-abiding citizen would do, like reaching for identification when approached by the police, or reacting in an erratic manner when set upon out of the blue.
If Wilson lit his pipe colleagues and journalists were suspicious, sometimes with good cause.
Sometimes the press are too suspicious, thinking that a museum cannot decide anything," Ms. Debo says.
