This knife cuts very well. 这把刀很锋利。 (1) 改为否定句 —> This knife doesn't cut very well. 这把刀不太锋利。 (2) 改为“这把刀根本没办法切东西” —> This knife doesn't cut at all.（句型 not...at all 表示“根本不……”） (3) 改为 Do you think...? “不认为”开头的疑问句 —> Do you think this knife cuts very well? 你觉得这把刀锋利吗？ ABC department store is having a sale this week. ABC百货公司这星期正在大减价。 (1) this week 改为 last week —> ABC department store had a sale last week. ABC百货公司上星期大减价了。 (2) 改为疑问句 —> Is ABC department store having a sale this week? ABC百货公司这星期正在大减价吗？ (3) 改为以 when 为开头的将来时疑问句 —> When will ABC department store have a sale? ABC百货公司什么时候大减价？