根据语意的需要，be+不定式结构中不定式可以用被动式。如：
The cover is not to be removed. 这块盖布请勿揭开。
This medicine is to be taken hourly. 这药每小时服一次。
The cost of carriage is to be paid by the receiver. 运费由收货人支付。
She will determine how it is to be done. 她会决定这件事的做法。
A little tiredness after taking these drugs is to be expected. 服下这些药后会有些疲倦。
上一篇： 高考英语语法：虚拟条件句的三种基本类型
下一篇： 英语基础语法：名词单数变复数的方法
Meet China prospect Yi at NBA
阿里那斯膝伤将缺阵2-3个月 Arenas out 2-3 months with knee injury
Chinas Dong a great promise for Man Utd - Gill
Houston beats Utah to take lead in series
Suns PSV retain the Dutch soccer league title
Mavs keep cool, tie series with Warriors
退休播音员被邀请奥运播音Retired sportscaster invited for Olympics
Rooney strikes as Man United go six points clear
Bosh helps Raptors top Nets, even series
国际英语资讯:Americans desire for major third party surges: poll
Charlton suffers relegation in Premiership
HK shuttler wins first match at Singapore Open
Yao no longer NBAs big man in China as Kobe rules
莎拉波娃因伤退出意大利公开赛
Yao, Tracy named All-NBA 2nd Team
Ohio States Oden plans to enter draft
教练：陈宏的回归对中国是个坏消息
诺维斯基成为NBA的MVP
Figure skating champions to tie knot
Brazilian player booked for kissing ref