the main cause of (某種現(xiàn)象) is due to (最主要原因). it is high time that something were done upon it. for one thing,話題作文, there are more and more (某種現(xiàn)象) in (某種場(chǎng)合). it is estimated that (相關(guān)數(shù)據(jù)). why have there been so many (某種現(xiàn)象)? maybe the reasons can be listed a