请问以下这句话为什么不用被动语态?All things considered,the planned trip had to be called off.为什么不用be considered?

请问以下这句话为什么不用被动语态?All things considered,the planned trip had to be called off.为什么不用be considered? The search proved difficult.这句话为什么不用被动语态这句话为什么不用被动语态?如果用被动在proved前面加个was就可以了吧 请问这句话为什么不用被动语态? The hunt for the puma began in a small village不用被动语态?把began换成started也不要用被动吗?还有As the evidence began to accumulate……,这里也没用被动,换成started呢?要不要 请问这句话为什么不用被动语态?The hunt for the puma began in a small village不用被动语态?把began换成started也不要用被动吗?还有As the evidence began to accumulate……,这里也没用被动,换成started呢?要不要用 关于被动语态,My pets take a lot of time to look after.这句话中,宠物是被人照顾的,为什么不用被动呢? 请问这里为什么不用被动语态?语法书里写到,有一种动词可用做及物和不及物动词,这涉及宾语变为主语的情况,如：He opened he door.The door opened.请问第二句应该是被动语态形式吧? Her eyes were fixed on her plate and in a short time,she was busy eating.这句话中的were fixed.怎样理解,是不是被动语态,要是被动语态,为什么不用was,而用were. They have all been put to shame by a boy这句话说是被动语态,改为主动语态怎么改, It's well-known to all that...请问这句是系表结构还是被动语态?　TO　ALL在句中做什么成分?为什么? 请问以下这些词是没有被动语态的吗? 请问以下这些词是没有被动语态的吗? 请哪位帮忙看一下以下英文句子是否正确.请哪位帮忙看一下以下句子是否正确.我认为这句话应该要用被动语态吧,但为什么 postponed 前不用 be 动词?Please note that the meeting has postponed to this aftern 这句话是不是被动语态This piece of orchestral music is write by Wagner .这支管弦乐曲是瓦格纳写成的.write不用改变形态吗 为什么 这句话从句that..为什么不用被动语态呢I assumed that she was above reproach.我认为她不应受到责备. 为何不用被动语态健康讲座明天上午9点开始这句句子中以健康讲座作为主语,为什么不用将来时态的被动语态 这句话是被动语态吗 umbrellas sell best 中的sell 为什么不用被动语态 为什么用现在分词而不用被动语态呢?