1. If there's heavy traffic on the main road, take the alternative route through the back streets.
如果主要道路上交通拥堵，可以选择通过小巷走替代路线。

2. The bridge is closed for repairs, so we'll have to find an alternative route to get to the other side of the river.
桥梁因维修而关闭，我们必须找到另一条通往河对岸的替代路线。

3. The hiking trail was blocked by fallen trees, so we had to find an alternative route to reach the summit.
徒步道被倒下的树木挡住了，我们不得不找到另一条通往山顶的替代路线。

4. The highway was closed due to a landslide, so drivers had to take alternative routes to reach their destinations.
因为山体滑坡，高速公路被关闭，司机们不得不选择替代路线到达目的地。

5. The usual route to the airport was congested, so the taxi driver suggested taking an alternative route to save time.
通往机场的常规路线拥堵不堪，出租车司机建议选择替代路线以节省时间。

6. During the marathon, some streets will be closed to traffic, so make sure to plan an alternative route if you need to drive through the area.
马拉松比赛期间，一些街道将关闭交通，所以如果需要开车穿过该地区，请确保计划好替代路线。