整理 J 動詞や名詞の意味を広げる文法形式 教科書 p.96
The pattern expands the verb/noun meaning
接続：Vます remove ます + かける／かけだ
in the middle of / almost. The action has begun but is not yet completed.
注意 / Note：Check the subject, tense and tone of both clauses; Avoid translating word for word from Vietnamese.
比較 / Compare：Compare with similar samples in the same article to choose according to nuance and connection. Same 課: 〜きる／〜通す／〜出す／〜やすい／〜にくい／〜づらい／〜すぎる／〜がちだ／〜らしい／〜っぽい／〜のようだ／〜みたいだ／〜だらけだ — these models are often mistaken for each other, read the 接続 line carefully and then decide.
読みかけの本が机にあります。
The unfinished book is on the table.
言いかけて、やめました。
I was about to say it.
書きかけのプログラムを保存して、会議に出ました。
I saved the program I was writing and then joined the meeting.