Does "chà" requires "dào" when expressing time? My Chinese teacher (a native speaker) told me that when using "chà", I need also to use ""dào", like this:


  chà shí fen dào 4 diăn. (3:50).


But I cannot find a single reference to this online. Everywhere, only chà is used, like:


  chà shí fen 4 diăn


or


  4 diăn chà shí fen
chà shí fen dào 4 diăn. (3:50)
差十分到四點 = &quot;(still) ten minutes to four o'clock&quot; = &quot;ten to four&quot; in English
It is English grammar directly applied to Chinese language. Chinese do not usually describe clock time this way. (Although it is based on English grammar, most Chinese would have no problem accepting it)

The normal way to describe 3:50 is &quot;三點五十分&quot;.
It is fine to say  &quot;還有十分鐘就四點&quot; or &quot;還差十分鐘就四點&quot; (still ten more minutes, and it will be four o'clock) to emphasize how close it is to four o'clock
chà shí fen 4 diăn 差十分四點 (it shorten 還差十分鐘就四點 too much, sound very blunt)
4 diăn chà shí fen 四點差十分 (no one say it like this)

when using &quot;chà&quot;, I need also to use &quot;&quot;dào&quot;

Yes there's a [差(chà) XXX 就到(Jiù dào) YYY] structure in Chinese grammar
For example &quot;差(十分鐘)就到(四點)&quot;
Sometimes people do omit 就 (Jiù) and say &quot;差十分鐘到四點&quot;
Sometimes people also omit '鐘' in '十分鐘' and just say '十分' in this structure