( )2.I went to my friend’s birthday party,but my dog ____________at home.

选C
这边的remain是做系动词 后面接介词短语作表语 另外注意 remain是不及物动词,不及物动词的意思就是后面不能直接加上宾语,所以没有被动
remain一词,用法较为复杂,将remain的用法归纳如下：
一、 用作联系动词,指某人或某事物仍保持某种状态,意为“仍然；依旧”,“留；呆；住；待”,后面可接名词、代词、形容词、介词短语、分词作表语.
1.接名词作表语
Peter became a manager,but Jack remained a worker.彼得成为了一个经理,而杰克仍然是个工人.
It remained a secret.这仍然是个秘密.
2.接形容词作表语
Whatever achievements you’ve made,you should remain modest.无论你取得多么大的成就,你都该保持谦虚.
3.接介词短语作表语
He had to remain in hospital until he was better.他不得不一直住院直到身体好些.
4.接分词作表语
接过去分词作表语,表示主语所处的状态或已经发生的被动动作；现在分词作表语,表示正在进行的主动动作.
The guests came in,but she remained sitting at the desk reading.客人们都来了,但她还坐在写字台旁读书.
As before,he remained unmoved.他和以往一样无动于衷.