When using a "te wa ikenai" construction, do you have to write "ikenai" without kanji, or can you use 行? For example: 働かなくてはいけない vs: 働かなくては行けない My understanding was that the idiom was ...
I know that a sentence that ends in the て form of a verb can be imperative. How do you know for sure if it is? Why is「～しようとして」not imperative?