单选题 They (couldn't) decide (whether) they should (leave) the theater or (to stay there).
A. couldn't B. whether C. leave D. to stay there

【正确答案】 D
【答案解析】[解析] 应改为stay there。句中的whether...or是表示选择的并列连词，因此or后面的语法成分要和前面保持一致。