As soon as V
This pattern expresses that an event happens immediately after another, often used in spoken language or informal contexts.
Examples
会議が始まるが早いか、彼は遅れて到着した。
As soon as the meeting started, he arrived late.
彼が出かけるが早いか、雨が降り出した。
As soon as he went out, it started to rain.
電話が鳴るが早いか、彼女は出かけて行った。
As soon as the phone rang, she went out.
Quick check
会議が始ま___が早いか、彼は遅れて到着した。