we must have missed the bus. i think _____.

so
这应该不是一个人说的，前面的话是一个人说的，后面另外一个人回答：“我也是这么认为的”

我想我们一定是错过公车了。

we must have missed the bus. i think __we should have come a bit early___.

we must have missed the bus. i think _____.
1. we should take other transpotation.我们应该搭乘其他交通工具(同一人说话)
2. so. 我也这样觉得.(另一人说话)
3. our plan melt into thin air.我们的计划泡汤了(两人都可说)

so