________ you've got a chance, you should make full use of it.
—Which umbrella can I take? —You can take______of them; I will use none.
Living in the desert involves a lot of problems,______water shortage is the worst.
Only when you have obtained enough data______ come to a sound conclusion.
Lessons______easily are soon forgotten.
If the building project______by the end of this month is delayed,the construction company will be fined.