A ball of yarn or thread.
线团，纱团丝线球或线球
The curve ball is also called arc line ball.
曲球打法又叫弧线球。
Curve ball: A pitch thrown with a rotation that makes the ball curve.
曲线球：投出旋转球，使球的飞行线路呈曲线。
down-the-line shot
沿边线打击的直线球
spherical indicatrix of binormal to a curve
曲线副法线球面指标
a cricket ball bowled as if to break one way that actually breaks in the opposite way.
投手以内曲线球投法投出的外曲线球。
Change-up: A pitch thrown deceptively slowly to surprise the batter.
变线球：用虚假慢动作投球，奇袭击球员。
To hit(a ball)sharply, usually in a straight line.
击出边线快速直线球通常沿着直线方向猛击（球）
touchdown running
举球越过对方球门线
a line from which basketball players take penalty shots.
棒球运动员的罚球线。
a sacrifice made by hitting a long fly ball.
打一个长线飞球的击球。
She tried to shoot from outside the free-throw line.
她试着从罚球线外投球。
spherical indicatrix of tangent to a curve
曲线切线的球面指标
Back Boundary line
端线(单打后发球线)
midfield stripe
足球场中线,五十码线
To begin or resume play with a kickoff.
开球开始球赛或中线开球
The swerving of a ball from a straight path of flight, as in baseball or cricket.
曲线飞行棒球或板球运动中球的曲线飞行
The ball is not out of play until the entire ball has crossed over the touch line_or_goal line.
足球整个都出了边线、底线或球门线时，才造成死球。