当孩子们由父母陪同时，他们才被允许进入这个运动场。

　　三、过去分词(短语)作状语时几点特殊情况

　　1．过去分词在句中作时间、条件、原因、让步状语时，相当于对应的时间、条件、原因及让步状语从句。

　　Seen from the top of the mountain(＝When it is seen from the top of the mountain), the whole town looks more beautiful.

　　从山顶上看，整个城市看起来更美了。

　　Given ten more minutes(＝If we are given ten more minutes), we will finish the work perfectly.

　　如果多给十分钟，我们会完美地完成这份工作。

　　Greatly touched by his words(＝Because she was greatly touched by his words), she was full of tears.

　　由于他的话深深地感动了她，她满眼泪花。

　　Warned of the storm(＝ Though they were warned of the storm), the farmers were still working on the farm.

　　尽管被警告了风暴的到来，农民们仍在农场干活。

　　2．过去分词在句中作伴随、方式等状语时，可改为句子的并列谓语或改为并列分句。

　　The teacher came into the room, followed by two students(＝ and was followed by two students).

　　后面跟着两个学生，老师走进了房间。

　　He spent the whole afternoon, locked in his study(＝ and was locked in his study)．

　　他把自己锁在书房里度过了一整个下午。

　　3．过去分词作状语可与之对应的状语从句互换。而从句连词改成过去分词作状语时有时还可保留连词，构成"连词＋过去分词"结构作状语。

　　Even if I am invited(＝Even if invited), I will not take part in the party.

　　即使被邀请，我也不会参加那个宴会。

　　Unless you are asked to speak (Unless asked to speak), you should remain silent at the meeting.

　　除非被要求说话，在会上你应该保持沉默。

　　If it is merely drawn on your imagination (＝If merely drawn on your imagination)，the report will not be convincing.

　　假如仅靠你的想象去写，报告是不会有说服力的。

4．过去分词(短语)的独立结构。过去分词(短语)作状语时，其逻辑主语通常是句子的主语，否则，过去分词(短语)前应加上自己的主语，这种带有自身主语的过去分词(短语)被称为过去分词(短语)的独立结构，过去分词(短语)的独立结构通常在句中作状语，可表示时间