If you have a holiday, why not ________ on a trip?

They will build a new bridge _____ the river in front of my house.[ ]

How did the accident happen? —You know, it ________difficult to see the road clearly because it_________.

How do you like my new T-shirt? I ________ it on my way here.

scientists have done a lot of research on A (H1N1) flu, there are still some cases for further study.[ ]