HE has been in hospital for a few days because he had his leg hurt 有错吗答案给的是SINCE不是BECAUSE 为什么空格就是BECAUSE

HE has been in hospital for a few days because he had his leg hurt 有错吗答案给的是SINCE不是BECAUSE 为什么空格就是BECAUSE
HE has been in hospital for a few days because he had his leg hurt 有错吗
答案给的是SINCE不是BECAUSE 为什么
空格就是BECAUSE

HE has been in hospital for a few days because he had his leg hurt 有错吗答案给的是SINCE不是BECAUSE 为什么空格就是BECAUSE
since because, as, for, since这几个词都是表示“原因”的连词,语气由强至弱依次为：because→since→as→for;其中because, since, as均为从属连词,引导原因状语从句；而for 是并列连词,引导并列句.
1. because表示直接原因,它所指的原因通常是听话人所不知道的,其语气最强.常用来回答why的提问,一般放于主句之后,也可以单独存在.例如：
(1)I stayed at home because it rained. 因为下雨我呆在家里.
(2)Because Lingling was ill, she didn”t come to school. 玲玲因病,没有上学.
(3)�Why is she absent? 她为什么缺席?
�Because she is sick. 因为她病了.
此外,在强调句型中,只能用because.例如：
(4)It was because I missed the early bus that I was late for school. 我上学迟到是因为我没有赶上早班汽车.
2. since侧重主句,从句表示显然的或已为人所知的理由,常译为“因为”、“既然”,语气比because稍弱,通常置于句首,表示一种含有勉强语气的原因.例如：
(1)Since he asks you, you”ll tell him why. 他既然问你,那就告诉他为什么吧.
(2)Since everyone is here, let”s start. 既然大家都到齐了,我们就出发吧!
(3)Since I understood very little Japanese, I couldn”t follow the conversation. 我日语懂得不多,因而听不懂对话.
3. as是常用词,它表示的“原因”是双方已知的事实或显而易见的原因,或者理由不是很重要,含义与since相同,但语气更弱,没有since正式,常译为“由于,鉴于”.从句说明原因,主句说明结果,主从并重.例如：
(1)We all like her as she is kind. 我们都喜欢她,因为她善良.
(2)As I had a cold, I was absent from school. 因为我感冒了,所以没去上课.
(3)As Xiaowang was not ready, we went without him. 由于小王没有准备好,我们只好不带他去了.
4. for用作连词时,与because相似,但它所表示的原因往往提供上文未交待过的情况.for不表示直接原因,表明附加或推断的理由,因此for被看作等立连词,它所引导的分句只能放在句子后部(或单独成为一个句子),并且前后两个分句间的逻辑关系不一定是因果关系,其间用逗号隔开,且for不可置于句首,for的这一用法常用在书面语中,较正式.例如：

(1)The days are short, for it is now December. 白天短了,因为现在已是十二月份.
(2)It must have rained, for the ground is wet. (从“地面潮湿”作出“下过雨”的推测,但地湿并不一定是下雨所致, for不可以换为because.)
(3)The ground is wet because it has rained. (“下雨”是“地上潮湿”的直接原因.)
前后两个分句间有一定的因果关系时(有时很难区分是直接原因,还是推测性原因),for与because可以互换使用.例如：
(4)I could not go, for / because I was ill. 我没能去,是因为我病了.
(5)He felt no fear, for / because he was a brave boy. 他没有害怕,因为他是个勇敢的男孩
此题解析： He has been in hospital for a few days Since he had his leg hurt .由于此句用的是现在完成时态 has been , 所以可以推测出此句用since表示“自从”（ 注意：since一般和现在完成时态连用,表示“自从 某时起,..如何如何”）此句应理解为：自从他伤了他的腿以后,他就一直住在医院住了好几天了.
如果是 题目要让填 because 原因,题目就会是 He was in hopital because he had his leg hurt.

没有错！

空格在哪？