第一句：When will the tour bus leave?

游览车什么时候开呢?

A: Excuse me. When will the tour bus leave?

请问游览车什么时候开?

B: In three minutes.

3分钟以后。

A: When will it get to the terminal?

什么时候到终点站呢?

B: 1: 30.

一点半。

第二句：How often does the bus come?

间隔多久来一趟公交车呢?

A: Excuse me. How often does the bus come?

请问多久来一趟公交车呢?

B: 20 minutes.

20分钟。

相关表达法：

What time does the tour bus leave? 旅游车什么时候出发呢?

观光游览车用英语说是：sightseeing bus 或者说 tour bus。