_____ the doctors really doubt is _____ my mother will recover from the serious disease soon.
_____ she was sick, I was expected to take his place greatly surprised me, for I didn’t have much work experience.
—Did you have any difficulty catching yesterday’s lecture?—No. The professor spoke very clearly to make his speech easy _____.
After months of voyage, Columbus arrived in _____ later proved a new continent.
—Do you think our team will win the game?—I don’t know. But this is the last chance. We _____ them to.
____ our natural resources is very necessary.