外源物

Two couples of primers were synthesized according to the sequence of the pelA gene. They are used to prove that the pelA gene obtained from NTT33 by PCR.

根据核苷酸序列分析结果设计引物，通过PCR的方法，在嗜碱芽孢杆菌NTT33的总DNA和p1350中分别扩增到预计大小的片段，证明pl350中的外源DNA片段来自於嗜碱芽孢杆菌NTT33。

We have no common name for a mime of Sophron or Xenarchus and a Socratic Conversation; and we should still be without one even if the imitation in the two instances were in trimeters or elegiacs or some other kind of verse--though it is the way with people to tack on 'poet' to the name of a metre, and talk of elegiac-poets and epic-poets, thinking that they call them poets not by reason of the imitative nature of their work, but indiscriminately by reason of the metre they write in.

索夫农 、森那库斯和苏格拉底式的对话采用的模仿没有一个公共的名称；三音步诗、挽歌体或其他类型的诗的模仿也没有——人们把&诗人&这一名词和格律名称结合到一起，称之为挽歌体诗人或者史诗诗人，他们被称为诗人，似乎只是因为遵守格律写作，而非他们作品的模仿本质。

The relationship between communicative competence and grammar teaching should be that of the ends and the means.

交际能力和语法的关系应该是目标与途径的关系。