I missed the last bus and had no money for a taxi; so I could do nothing but_______ home last night.
The government is trying to ______ pollution to an even lower level so that we can have a better environment.
At times the balance in nature is ______, resulting in a number of possibly unforeseen effects.
Congratulation! It seemed that our boss was ______ with your work today.
The boy lay on his back, with his teeth ______ and his glaring eyes ______ straight upward.
_______ in the leg made it impossible for me to walk as fast as usual.