【正文】
固對(duì) must have been doing,preventfrom doing Step 3 問題探究 。 (完成句子 ) Tom_____ ______ _______ _________basketball. must have been playing。 must have been doing:表 boy______ ______ (prevent) from climbing up the tree just now. was prevented。句意為:剛才阻止了那個(gè)男孩爬樹。 課后評(píng)價(jià)方案 1. 2b。