is couched in

５月２５日のThe Japan Times Onlineの 'Understanding the extent of Chinese public support for Russia' の記事から引用します。

A full 75% of the surveyed respondents indicated that supporting Russia in the Russo-Ukrainian conflict is in China’s national interest. What is worth noting here, however, is that the survey question is couched in terms of interest, as opposed to asking whether the war was right or justifiable. Respondents were not invited to reflect upon the most morally upright course of action, but what they deem the most prudential and instrumental course of action for China to take. One cannot help but ponder if a slightly reworded question (with greater emphasis placed upon how China should act, all things considered) would yield different results.

"is couched" の個所が分からないので、"couch" を辞書で見ます。

・Oxford English Dictionary: (usually be couched in) Express (something) in language of a specified style.: ‘many false claims are couched in scientific jargon’
・Collins Dictionary: If a statement is couched in a particular style of language, it is expressed in that style of language.: This time the proposal was couched as an ultimatum.
・Cambridge English Dictionary: to express something in a particular way: I don't understand this form - it's all couched in legal terminology.

これは憶えておくべき表現ですね。