1.【棒】指节球,指关节球
1.in baseball, a slow pitch with little spin and an unpredictable flight, produced by releasing the ball from the knuckles and the thumb or the tips of two or three fingers
1.Shifting an Internet friendship into the real world can be trickier than hitting a knuckleball.
将网络友谊搬到现实世界要比投蝴蝶球更加困难。