they are hollow,which makes them very light 中,which 指什么?请指教

they are hollow,which makes them very light 中,which 指什么?请指教 hollow The are hollow in the middle. HOLLOW怎么样 hollow是什么意思 hollow是什么意思 They are they are Are they They are -------are they?they are --------(tomato) 1:Although they plant trees in this area every year,the tops of some hills are still___.A:blank B:hollow C:vacant C:bareblank和bare都有空白的意思,该选哪个呢?2:There's an opinion___ on the facts.A:based B:basing C:that base D:which base3: 用动词的适当形式填空China has many——(city).They are pretty. Chongqing is ——(beautiful) than Lhasa.Shanghai is——（big）than Shenzhen.Whic man is——（fat),Tom,Tim ,or Kim?Guangdong —— (have)many rivers. somewhere i never traveled,glady any experience,your eyes have their silence：in your most frail gesture whic enclose me,or which i cannot touch because they are too near.your slightest look will easily unclose me,though i have myself as fingers 这 英语问题（专业人士进）（1）They are the principles,many of them,which I learnt at my mother's knee.这里的many of them是插入语吗?插入语不会造成语法错误?后面的那个which是修饰principle还是many?（2）As for whic hollow 这个词怎么记? 翻译Rectangular Hollow Section HOLLOW MAN怎么样