The doctor　　　the farmer sent his son is well-known in the field.

Have you seen my iPhone 5 I left it here this morning.— Is it black one I think I saw it somewhere.

The possibility____ pleasant smells might reduce pain has recently been suggested by new research.

We need to spend more time researchingthese suggestions so that we can make a(n)choice.

Which of the two books will you take, Franklin—I’ll take _____ though I find _____ of them very useful to me.