The phrase "are sometimes silent" is correct and usable in written English.
You can use it to describe situations or subjects that do not always express themselves or are not always vocal.
Example: "In discussions about sensitive topics, people are sometimes silent, choosing instead to listen and reflect."
Alternatives: "may occasionally be quiet" or "can be mute at times".
Proteins can be classified into four types, according to the consequences of the binding event: receptors, metabolizing enzymes, protein carriers, and the remainder, which are sometimes called silent receptors.
"Even if you say it is not true, you will eventually have this connection with Saddam Hussein and 9/11". The psychologist acknowledged that such a statement might not be entirely accurate -- issuing a denial or keeping silent are sometimes the only real options.
This majority is what is sometimes called "Silent Catalonia".
Further separators and digits are sometimes used to describe allelic variants that contain silent nucleotide differences.
"We [the committee members] believed that having to memorize a poem and perform it vocally creates an intimacy between poem, poet and performer that is sometimes missing in silent, solitary reading," Kim said.
For this reason the provilege to be silent is sometimes accepted as being more or less of a constitutional nuisance which the courts should abate whenever and however possible.
"The president has followed this issue personally, continually, assiduously and actively in the last few days," Mr. Soubie said, adding, "With social issues, it is sometimes better to be silent than to be on stage, if you want to be efficient, if you want the strands of dialogue to be there and to be knit together".
It is sometimes described as the silent, reflective 'observer' of the human condition.
This silent agreement is sometimes emotional, physical or even spiritual – tearful scenes, jelly beans and refreshing streams are commonly shared between strangers and rivals alike.
