If we        take environmental problems seriously, the earth         worse and worse.

I don’t know if it        tomorrow. If it       tomorrow, I won’t go to play basketball.

—Shall we go for a picnic in the forest park tomorrow?
—Yes,         it rains heavily.

Nothing in the world is difficult        you put your heart into it.

       you don’t give up, your dreams will come true.

The rivers will become dirtier and dirtier        we take action to protect them.

      we’re late for the lesson, the teacher will get angry.

用所给词的适当形式填空，每空一词。
If we ask people ____ ____ (bring) food, they ____ ____(bring) potato chips.

根据汉语意思完成句子，每空一词。
如果他成了职业运动员，全世界的人都会知道他。
If he becomes a professional player, people around the world ____ ____ ____.

根据汉语意思完成句子，每空一词。
假如周六苏珊来这，她就会组织这场会议。
If Susan comes here this Saturday, she ____ ____ the meeting.