In fact fuels we burn and plant food we eat ________ their chemical energy in the form of heat.
Personally I think it is the sales manager, rather than the sales girls, _______ to blame.
Everything depends on ________ we have enough time.
Mother made a promise ____ I passed the college entrance examination she would buy me a mobile phone.
---Why did you put the wood near the fire? It’s dangerous. ---Don’t worry. Wet wood won’t _______.
He’s unlucky, and he’s always suffering _____ luck one after another.