帮忙解释下英语语法Bill has a really hard time paying attention上句为什么不是

帮忙解释下英语语法Bill has a really hard time paying attention上句为什么不是 前面说他成绩不好,但是每天还假装开心,为了给别人好印象,紧接着是：Bill has a really hard time 为什么是through a really hard time 而不是through really a hard time Nancy suggested the bill worth paying attention _____at the The advice given was really worth paying attention.改错 really hard有几种解释? I had a really hard time with science 中的 really hard 有什么作用 I had a really hard time to science this semester. 翻译：it was a really hard time for me I really had a hard time with history. 英语：i had a hard time getting through this novel 这里为什么不是to he 英语语法解释The animal has a brain which is nearest____横线上填in size