3：Few people ask by what ___________the writers of dictionaries and grammars say what they say. 选择 2.intention
4： walk is expected to last all day, so bring packed lunch. 选择 3.The ; a
5：I have longed to _____ my study abroad. 选择 2.further
6：Americans often greet each other simply ______ “Hello” or “Hi”. 选择 3.with
7：The discovery of antibiotics marked the beginning of a new ______ in medical research. 选择2.era
8：Great as Newton was, many of his ideas _______ today and are being modified by the work of scientists of our time. 选择3.have been challenged