【单选题】
Youhavetopaytohavethebooksprinted, ____ canbequiteexpensive.
【单选题】
Early to bed and early to rise ____ a man healthy, wealthy and wise. ?
【单选题】
People often ____ the old days ____good times, and seem to forget the hardship they suffered.
【单选题】
This is the ____ photo I have ever taken.
【单选题】
____ these honors he received a sum of money.
【单选题】
Before taking off, they were asked to ____ their seat-belts.
【单选题】
In HangzhouMr. Green was so struck by____ beauty of ____ nature that he stayed for another night. ?
【判断题】
<img src=http://huaweicloudobs.ahjxjy.cn/db7e488fc9e00874c3c04fefca18a12c.png/>
【判断题】
<img src=http://huaweicloudobs.ahjxjy.cn/d440a6ee7d5e801708929dcf6917d364.png/>
【判断题】
在环中,左零因子与右零因子同时存在或同时不存在。