a ray of light
一筋の光線
a reliable source
信頼できる筋
A series of dots marks the route.
点線が道筋を示している
A shiver ran up [down] his spine.
彼は背筋がぞくっとした
a straight posture
背筋の伸びた姿勢
a stretch of road
一筋の道路
a thread of sunshine
一筋の日の光
a twist of smoke
一筋のよじれた煙
a voluntary muscle
随意筋
a wisp of smoke [a cloud]
一筋の煙[一片の雲]