求分析英语小句子结构It was late,and by that time they were feeling qui

It was late,and by that time they were feeling quite happy.
and 连接的两个并列句,用逗号隔开；
by that time 在后半句中式时间状语,后面是过去进行时.
One of them got in with his head at the top of the bed.
One of them got in 这是句子的主干,主谓结构；
with his head at the top of the bed 这一小节是with的伴随结构,做伴随状语.

It was late, 时间状语 放在句子开头。没什么问题吧，后面就简单的主谓宾。One of them是主语got in with his head谓语和宾语，最后at the top of the bed.状语。 呵呵。希望能帮到你。

It was late, and by that time they were feeling quite happy. 由两个句子组成的并列句。by that time是修饰they were feeling quite happy的时间状语。
One of them got in with his head at the top of the bed. 主语One of them，谓语got in， with his head at the top of the bed 介词短语做状语。