That's where power and topspin come in.

那就是力量和上旋发挥作用的地方。

Since a curveball has topspin, that means the air behind it gets deflected upwards.

由于弧线球具有上旋球， 这意味着它后面的空气会向上偏转。

You gotta put that topspin on it.

你得给它加上上旋。

Man wouldn't know topspin if it hit him in the ball sack.

被击中下身才会知道上旋球的厉害。

That's why Serena also uses topspin to her advantage, usually when her first power serve goes out of bounds.

这就是为什么塞雷娜也会利用上旋的优，通常是在她的第一次强力发球出界时。

But topspin serves are more accurate and still difficult to return.

但上旋发球更准确，仍然很难被回击。

Think of Nadal's swing; everything he does is to impart strong topspin on the ball.

达尔的挥杆;他所做的一切都是为了在球上赋予强大的上旋球。

However, it has a high topspin, and it's awkward to return.

然而，它带有强烈的上旋，回球起来很别扭。

That's because the topspin on the ball forces it to drop sharply right before it reaches the opponent.

那是因为球上的上旋迫使球在接近对手之前突然下坠。

Understand the importance of topspin and using lobs to get the ball over the net at a higher trajectory.

了解上旋球和使用吊球以更高的轨迹将球越过网的重要性。

It created a string bed that generated so much topspin that it was quickly banned by the International Tennis Federation.

它创造了一个产生如此多上旋球的弦床，以至于它很快被国际网球联合会禁止。

So, Serena could be about to deliver a topspin serve, a power serve, or even a slice serve.

所以，塞雷娜可能会发出上旋发球、强力发球甚至切削发球。

For example, Serena's average topspin serve is about 145 kilometers per hour, 25 kilometers per hour slower than her power serve.

例如，塞雷娜的平均上旋发球时速约为145公里，比她的强力发球慢了25公里。

Because you see, the open stance shot doesn't have that topspin, and in an actual match, it can save two seconds.

因为你看， 开放站姿击球没有那个上旋球，在实际比赛中， 它可以节省两秒钟。

As long as you follow the eight-step practice method we mentioned last time, can control the ball, play some gentle rallies with others, understand what a topspin stroke is, and can turn your shoulder, that's a 2.5 level forehand.

只要按照我们上次提到的八步练法，能控球， 能跟别人打一些温和的拉球，明白什么是上旋球，能转肩， 那就是 2.5 级的正手。

As long as you follow the eight-step practice method we mentioned last time, and can control the ball, play some gentle rallies with others, understand what a topspin stroke is, and can turn your shoulder, that's a 2.5 level forehand.

只要按照我们上次提到的八步练法，并且会控球， 跟别人打一些温和的拉球，明白什么是上旋球，能转肩， 那就是 2.5 级的正手。