primary source text

The 140 character limit is necessary only because text messages, one of Twitter's primary source channels, are similarly constrained.

（140 字符的限制完全来自文本消息，它是 Twitter 的主要来源渠道，并受到类似的限制）。

Examine all allusions found within the text by tracing their roots to the primary text or source, if possible.

精细研读文本中的所有用典，如有可能，对用典要刨根问底。

Machine set up kiln dust pollution primary pollution source of cement plant, to set up this text kiln cement plant dust removal these difficult problem carry on research.

为了解决机立窑粉尘污染源问题，针对立窑水泥厂除尘这个难题进行了研究。