選C.句意：一些作物吸收我們呼出的二氧化碳而給我們呼出氧氣作為回報(bào).A.in case 萬一；假使B.in turn 輪流,依次=by turns,in file；轉(zhuǎn)而,反過來（強(qiáng)調(diào)“按順序輪流過來之后又轉(zhuǎn)向”）C.in return 作為回報(bào)；作為…的....in turn反過來（強(qiáng)調(diào)“按順序輪流過來之后又轉(zhuǎn)向”）能就此點(diǎn)給個(gè)例句嗎，最好來個(gè)和in return 作對(duì)比的Teachers are more responsive to you, people treat you better; you have more opportunities to make your way through the world; you make more money; you have more access to things,;and that could, in turn, cause you to improve your life. 老師更喜歡回應(yīng)你，人們待你更好，你有更多的機(jī)會(huì)闖出自己的一條路，你賺到更多的錢，你能得到更多的東西，從而使你能改善你的生活。If you are alwayshelpingothers, you will be helped in turn when you need help.I just didn't want to take anything If I couldn't offer anything in return. We'd be happy with just one dance. 如果我不能給予回報(bào)的話,我不想接受任何東西。如果能跳個(gè)舞，我們就很高興了。We should try our best to our life to the full in return for the kindness of our parents.