You are about to enter the main lanes of an expressway along the acceleration lane at an interchange. Vehicles are traveling at a steady speed in the outer main lane. What is the most appropriate way to drive?

1. ①The entering car has priority, so turn on the turn signal and move straight into the main lane.
2. ②Stop in the middle of the acceleration lane and wait until main-lane vehicles slow down for you.
3. ③Build up enough speed in the acceleration lane and enter at a gap where you will not obstruct main-lane traffic.
4. ④When a main-lane vehicle approaches, sound the horn to ask it to make way.