自由球，规则中原文为nominated ball
即选手犯规后做到斯诺克，可以选择任意一颗球当作合法目标球来击打。
例如，
比赛中，希金斯犯规，轮到阿伦击球，他当前的目标球为红球，但是红球全部被挡（即犯规后做到斯诺克）。
这时阿伦可以选择任何一颗彩色球当作红球击打，他选择了黄色球。
击落黄球相当于击落红色球，加一分。
阿伦继续击球，该下来该击打彩色球，他可以选择六个彩球的任意一个球来击打。
他又选择击打黄球，这时击落黄球就是黄球的分值，加两分。
这就出现了连续击打两次黄色球的情况
粘贴官方规则原文中相关条款如下：
（留意看规则中对于斯诺克（即障碍球）的定义）
SECTION 2. DEFINITIONS
12. Nominated Ball
(a) A nominated ball is the object ball which the striker declares, or indicates to the satisfaction of the referee, he undertakes to hit with the first impact of the cue-ball.
(b) If requested by the referee, the striker must declare which ball he is on.
16. Snookered
The cue-ball is said to be snookered when a direct stroke in a straight line to every ball on is wholly or partially obstructed by a ball or balls not on. If one or more balls on can be struck at both extreme edges free of obstruction by any ball not on, the cue-ball is not snookered.
(a) If in-hand, the cue-ball is snookered if it is obstructed as described above from all possible positions on or within the lines of the "D".
(b) If the cue-ball is so obstructed from hitting a ball on by more than one ball not on
(i) the ball nearest to the cue-ball is considered to be the effective snookering ball, and
(ii) should more than one obstructing ball be equidistant from the cue-ball, all such balls will be considered to be effective snookering balls.
(c) When Red is the ball on, if the cue-ball is obstructed from hitting different Reds by different balls not on, there is no effective snookering ball.
(d) The striker is said to be snookered when the cue-ball is snookered as above
(e) The cue-ball cannot be snookered by a cushion. If the curved face of a cushion obstructs the cue-ball and is closer to the cue-ball than any obstructing ball not on, the cue-ball is not snookered.
SECTION 3. THE GAME
10. Snookered After a Foul
After a foul, if the cue-ball is snookered, the referee shall state FREE BALL (see Section 2, Rule 16).
(a) If the player next in turn elects to play the next stroke,
(i) he may nominate any ball as the ball on, and
(ii) any nominated ball shall be regarded as, and acquire the value of, the ball on except that, if potted, is shall then be spotted.
(b) It is a foul if the cue-ball should
(i) fail to hit the nominated ball first, or first simultaneously with the ball on, or
(ii) be snookered on all Reds, or the ball on, by the free ball thus nominated, except when the Pink and Black are the only object balls remaining on the table.
(c) If the free ball is potted, it is spotted and the value of the ball on is scored.
(d) If a ball on is potted, after the cue-ball struck the nominated ball first, or simultaneously with a ball on, the ball on is scored and remains off the table.
(e) If both the nominated ball and a ball on are potted, only the ball on is scored unless it was a Red, when each ball potted is scored. The free ball is then spotted and the ball on remains off the table.
(f) If the offender is asked to play again, the free ball call becomes void.
在对手犯规的情况下（并且白球形成死球，或者斯诺克的情况下）可以击打两次彩球用来走位！也计分
当一方因为失误犯规而给对方造成障碍球时，对方即取得自由球权，即可选择一颗彩球当作红球击打。这颗彩球按红球记分，接下来按正常规则击打彩球。这样便有了连续击打彩球的情况。
我刚才也看到了，那是因为希金斯没有解到球而且艾伦看不到红球，这时裁判判的自由球，就是艾伦可以选择任何一颗球当红球打，记一分，然后再打彩球。
这种情况属于自由球 自己去看看斯诺克的规则就清楚了 我个人表达能力有限 不好意思
