【问题征答】请各位老师剖析下列句子成分，尽可能全方位详尽，并找出一样的结构及例句。
Im at a loss which to choose.
下面我们的不成熟怎么看，不妥之处请刘老师指正！
▲句子成分剖析
句子是I，be at a loss为系表结构，但这里的 at a loss 为 at a loss for或at a loss as to 之省略，相在乎义上等于一个及物动词，其后的 which to choose 为宾语。比如：
Moved by their speech, I was at a loss what to say. 被他们的发言感动，我不知怎么说好。
I was at a loss for what to do next. 我不了解下一步该如何解决。
I’m at a loss as to how to explain the error. 我不知怎么样讲解这个错误。
其后的宾语也会是宾语从句。如：
She was at a loss which road she should take. 她不了解该走哪条路好。
I’m at a loss where I left it last time. 最后我把它放在什么地方，我目前一片茫然。
▲类似结构及例句
be at odds
The parents and teachers are still at odds about / over what to teach the students. 父母和老师对于教授学生什么内容建议不同。