在九球中，如果母球与目标球相吻，那么允许直接击出吗？

6.7 Double Hit / Frozen Balls
If the cue stick contacts the cue ball more than once on a shot, the shot is a foul. If the cue ball is close to but not touching an object ball and the cue tip is still on the cue ball when the cue ball contacts that object ball, the shot is a foul. If the cue ball is very close to an object ball, and the shooter barely grazes that object ball on the shot, the shot is assumed not to violate the first paragraph of this rule, even though the tip is arguably still on the cue ball when ball-ball contact is made.
However, if the cue ball is touching an object ball at the start of the shot, it is legal to shoot towards or partly into that ball (provided it is a legal target within the rules of the game) and if the object ball is moved by such a shot, it is considered to have been contacted by the cue ball.(Even though it may be legal to shoot towards such a touching or “frozen” ball, care must be taken not to violate the rules in the first paragraph if there are additional balls close by.)
The cue ball is assumed not to be touching any ball unless it is declared touching by the
referee or opponent. It is the shooter’s responsibility to get the declaration before the shot.
Playing away from a frozen ball does not constitute having hit that ball unless specified in the rules of the game.

个人翻译：
6.7 双击/贴球
如果在一次击球中球杆接触母球多于一次，则为犯规。如果母球接近但没有贴上目标球，击球时母球接触该目标球时杆头还和母球接触在一起，则为犯规。如果母球和目标球很近，选手击球时用母球轻轻擦过目标球，则，即便这次击球触犯了上一句的规定，也不判定为犯规。
但是，如果在击球前母球和目标球接触在一起，则往各个方向击球均是合法击球（假如接触的目标球是合法目标球的话）。如果接触的目标球移动了，则视为已经和母球接触。（即便往接触的目标球击打是合法的，也需要留意周围其他靠近母球的目标球，不能触犯本规则第一条。）
母球默认为没有接触任何球，除非有了裁判或则对手的声明。申请该声明的责任在于击球选手。
向反方向将母球击离一个接触的目标球，不视为母球已接触过该目标球，除非比赛细则里另有特殊规定。

这条规则是WPA在08.1.1实行的新规则里的第6章的通用规定，在黑八，九球，14.1等全部有效。

WPA(World Pool-Billiards Association)是世界小台落袋台球协会，这个协会不包含斯诺克，斯诺克的共有组织是WPSBA(World Professional Billiards & Snooker Association) ，斯诺克规则可以去他们的官方网站www.worldsnooker.com查看。我就不引用了，但斯诺克里这种球是必须击离接触的目标球的。

下面链接为规则下载点：