Helen is talking _________ her parents _________the phone.

Mum, can I go out and play with my friends now— Certainly, but your homework _________first.

Car drivers can take a subway into the city center ______ cars always get stuck in the traffic jams.

If you just spend time ________ advantages and disadvantages, you may get nothing in the end.[ ]

Jim made a nice cage _____________ the little sick bird till it could fly.