彼らの筋肉は硬直している。

Meaning
their muscles are rigid

Vocab used in this sentence

彼ら
they, their, them
の
to, of
筋肉
muscle, muscular, sinew, brawn
は
a, the, is, am, are, will
硬直
rigor, strictness, hardness, severity, harshness, stiffness, rigidity, inflexibility, sternness, hardship
し
and, shi, four, death
て
the, it, have
いる
are, to be, to stay, to have, necessary, to exist

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