然而，这种情况并不经常发生。
但是这种情况并不经常发生。
幸运的是，这种情况并不经常发生，对吗？
幸运的是，这种情况并不经常发生，对吗？
So what makes you most irritated is when someone tells you you're being "overly emotional."
在那一带水域轮船被冰冻住的事并不经常发生。
The ships were frozen in, which not frequently happens in those regions.
考试作弊并不经常发生，但一旦发生，学校会采取严厉的态度。
Cheating at exams does not occur very often. But when it does, the school takes a very tough position.
考试作弊并不经常发生，但一旦发生，学校会采取严厉的态度。
Cheating on exams does not occur very often. But when it does, the school takes a very tough position.
很不幸的是，这并不经常发生：目前我只收到四棵植物，你愿意给我点么？
Unfortunately, that doesn't happen too often: I've only got four plants now. Won't you send me a few more?
吉卜赛人拐小孩这种故事在世界的这个区域并不经常发生，不会有人相信。
Stories of gypsies, who steal children, are not AT all in vogue in this part of the world, and would not be believed.
如果一个男生开始用很严肃的语气讲话，听他说。这样的情况并不经常发生，所以发生的时候，你知道是出事情了。
If a guy starts to talk seriously, listen to him. It doesn't happen that often, so when it does, you know something's up.
花粉及杂交系统隔离并不经常发生，花粉隔离随优势种在数字上占优势而出现，但并不完全利用一系列的有利于传粉的动物(11)。
Pollinator and mating system isolation are less frequent, with the former arising when the focal species is numerically dominant but does not fully use the array of available animal pollinators (11).
花粉及杂交系统隔离并不经常发生，花粉隔离随优势种在数字上占优势而出现，但并不完全利用一系列的有利于传粉的动物(11)。
Pollinator and mating system isolation are less frequent, with the former arising when the focal species is numerically dominant but does not fully use the array of available animal pollinators (11).
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