1．Scientists ____________(猜想)that large dinosaurs lived in swamps.
2．I’ve really got nothing to ____________(抱怨)of.
3．At the moment，he ____________(宁愿)not to think about the future.
4．The experiment is ____________(打算将……用作)to test the new drug.
5．The old man entered the room ____________(支撑，支托，扶持)by his grandson.
