改錯：(2019·全國卷Ⅰ改編)Modernmethodsoftrackingpolarbearpopulat...

問題詳情：

改錯：(2019·全國卷Ⅰ改編)Modern methods of tracking polar bear populations are expensive performing consistently over a large area.

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【回答】

performing→to perform　此處是“主語＋be＋adj.＋不定式”結構，不定式用主動形式表被動含義。

知識點：非謂語動詞

題型：選擇題