Either that attribute should not exist (my preference), or it must have a value.
要么该属性不应该存在(根据我的习惯)，要么它必须有一个值。
The upshot is that so long as competition exists, transaction/institution costs must also exist.
结论是：只要竞争存在，交易或制度费用一定存在。
The method that you want to invoke must exist at compile time.
想要调用的方法必须在编译时存在。
First, we must postulate that if souls exist, they must have some mass.
第一，我们必须假定灵魂存在，他们必须保有物质。
EINSTEIN himself reckoned that, although they must exist, they would be impossible to spot.
爱因斯坦本人认为即便它们(暗物质)存在，人们也不可能观测到它们。
He feels that God is necessary and that he must exist.
他感觉到上帝是重要的，他必须存在。
He was too shrewd to believe that it must exist.
他坚信一定有——这一点上，他有点机灵过头了。
Hence, that object must exist.
因此，该对象必须存在。
If, however, you demand that you must have your pleasure at any price, then love will not exist.
然而，如果你想要那个，你就必然会不惜一切代价来获取快乐，那么爱就不会存在。
At this point, we must call into being technologies that do not yet exist.
这时候，我们必须呼叫现在还不存在的科技。
I must repeat that as a witness Mrs. Moore does not exist.
我必须重申，作为证人的摩尔太太是不存在的。
But we must be aware that factors endangering world peace and stability still exist.
但是我们必须时刻保持警惕，因威胁世界和平与稳定的因素还存在。
Ma Ning thinks that religion can't exist alone, it must grow together with life.
马宁认为信仰并不可能单独存在，而是必须要与生命成长同步。
To better understand the moral issues that exist, the project itself must be examined.
为了更好地理解存在的道德问题，对计划本身必须进行考察。
What can we do about this but cry to ourselves: "they will never exist any more, or they will exist for others," and do what must be done so that others at least do not go begging?
除了哀怨地自语：“它们将永远不复存在，就算存在也是属于别人的”，我们还能为此做些什么呢？为了使人们至少不必去乞讨，我们必须做些什么呢？
What can we do about this but cry to ourselves: "they will never exist any more, or they will exist for others," and do what must be done so that others at least do not go begging?
除了哀怨地自语：“它们将永远不复存在，就算存在也是属于别人的”，我们还能为此做些什么呢？为了使人们至少不必去乞讨，我们必须做些什么呢？
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