Unit4 Save the trees二，掌握下列句子释义：1. be harmful to sb =do harm to sb = be bad for sb（对.有害）2. Thank sb for (doing) sth = thanks for sb (doing) sth （感谢某人做某事）3. A lot = very much; a lot of = many/much （很多）5. Too. to = so.that = not.enough （太.以至于）6,be in (great) danger =be not safe （处于危险）7. Look after (well) = take (good) care （照顾）语法现在进行时：一、用法 1.表示说话时正在进行的动作。常和now，Look!Listen!。Eg1.I am reading a book now.Eg2.Look!They are having a basketball match.Eg3.Lis
