At an intersection with one lane in your direction, which action by the vehicle ahead prevents you from passing it on the left?

Passing at intersections is not always prohibited, but a single-lane left-side pass requires the right vehicle status, enough room and safety.

交差点での追い越しが常に禁止されるわけではありませんが、1車線内で左側を通過するには、前車の状態が条件に合い、十分な余裕と安全が必要です。