問題補充：
單選題
Alice was supposed _____ at home, but her mother found her surfing the Internet．A.studyingB.to be studyingC.to have studiedD.studied
網(wǎng)友答案：
熱心網(wǎng)友 1樓
B解析考查不定式的形式。Be supposed to do sth應(yīng)該做某事；本題使用進行時表示不定式動作和謂語動詞同時發(fā)生。句意：Alice被認為正在家里學(xué)習(xí)的，但是他的媽媽發(fā)現(xiàn)她在上網(wǎng)。本題的be supposed to be doing sth被認為正在做某事。故B正確。
