do you know that the population of Canada is much smaller than _______of China 为什在横线处用that?

Do you know that strike while the iron is hot ? Do you know the r___ that many birds died? Do you know that the cows have 4 s______. Do you know that ____(personal) at the gate? Do you parents know that? how do you know that the teenagers’ dreamshow do you know that the teenagers’ dreams can be quiet different? Idiots,know that you do not know do you know what's the matter?还是do you know what the matter is?为什么?do you know what's wrong with that?what 是什么成分？主语？ do you know that l love you Do you know the way? do you know the mean Do you know that what time the train leaves 改错,删去that,为什么呢? 翻译：Do you know the fact that the sun is bigger than the moon? Do you know中文歌词就是这个拉DO YOU KNOWDO YOU KNOW EnriqueDo you know Do you know Do you know what it feels like loving someone that’s in a rush to throw you away.Do you know what it feels like to be the last one to know the lock on the d Do you know that man ( ) white glasses? Do you know that( 国家) girl. Do you know that I'm Do you know who that American is