A car engine cannot run smoothly without motor oil.____ our body cannot function efficiently without vitamins.

The kite flew ______ in the sky and my father thought _____ of me. 

With the word“PM2．5"_____ appearing in media reports，people pay greater attention to it and seek health tips for smoggy days．

He speaks English well indeed, but of course not ________ as a native speaker.

I shall take you to France ________ you are well enough to travel.