请教英语不定式被动语态语法问题

Seven different gifts are to be distributed among 10 children.

意思是7件礼物将要被分给10个孩子。

你的改的那句，意思是礼物已经分给孩子了，但我觉得时态好像不合适，“Seven different gifts have been distributed among 10 children.” 比较好点。

礼物是被分发的，所以要被动。然后这里用了be to +infinitive,我觉得是有表示一个决定；或是将要发生的事（类似将来时）。具体的be to +infinitive的用法如下：

然后是关于"be to + infinitive"结构。

• We use be to + infinitive when discussing formal or official arrangements or to give formal instructions or orders and your examples illustrate these aspects very well. 

e.g. The Prime Minister is to make a further visit to Devon next week.

        We are to receive a pay rise in line with inflation in September.

• The be to + infinitive structure is also frequently used in newspaper, radio and television reports to refer to future events. It expresses near certainty that what is forecast will happen. Study the following:

       A man is to appear in court later this morning charged with the murder of the footballer, Darren Gough.

       Work is to begin this week on the new bridge across the Nile north of Aswan.

• We often use be to + infinitive in the if-clause in conditional sentences when talking about preconditions for something to happen. e.g.

       If we are to catch that train, we shall have to leave now.

• Be to + passive infinitive is often used when giving instructions. It is noticeable always on medicine bottles and can be seen on other official notices too:

e.g. To be taken three times a day after meals.

       No food of any kind is to be taken into the examination room.

Note that although this structure is used to talk about current and future arrangements and events, it is configurated in present and past tenses - see the above examples. However, be to + perfect infinitive is sometimes used to show that a planned event did not materialise:

e.g. He was to have appeared in the West End show but broke his collar bone during rehearsals.

They were to have picked strawberries this morning, but the torrential overnight rain made the field too muddy.