The letter "x" often represents a（n） （known） number in some Math exercises．
总而言之，只要你留心观察，生活处处充满美好。（all）
l ，life is always full of beauty as long as you watch carefully.
当我沮丧或疲惫时，我更喜欢看能让我振奋起来的电影。
When I'm down or tired，I movies that can cheer me .
我认为四月是泰国最热的月份。
I believe that is the month in Thailand.
我长大后想当一名工程师．
I want to be when I grow up．
好的学习者不害怕犯错。
Good learners are not afraid of .