我有一些朋友圈，我独自度过每个夜晚只是我的选择问题，而不是缺少可选择的项。
I have several groups of friends, and any evening I spend by myself is a matter of choice, not a lack of options.
还有一些额外的可选择行地补充和说明的属性，如：域名、描述。
There are a few additional properties which may be optionally added, such as site_name and description.
欧洲央行也可选择延长一些现有的计划。
The ECB also has the option of extending some existing schemes.
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