题目

51.  The volunteer devoted all her life to ___________ our environment. (improve) 52.        In the United States, lunch __________ to students for free at school. (offer) 53.        I found a wallet lying in the corner when I __________ the floor yesterday. (sweep) 54.        It is said that the director ___________ another comedy in Shanxi at present. (film) 55.        Do you know which shop he went to __________ the snacks? (buy) 56.  The woman looks excited because her favourite singer __________ on TV last night.  (interview) 57.        People wer下列表示对应化学反应的离子方程式正确的是A．向稀HNO3中滴加Na2SO3溶液：SO32－+2H+=SO2↑+H2OB．向Na2SiO3溶液中通入过量SO2：SiO32－+ SO2+ H2O=H2SiO3↓+SO32-C．向Al2(SO4)3溶液中加入过量的NH3·H2O：Al3++4NH3·H2O=AlO2－+4NH4++2H2OD．向CuSO4溶液中加入Na2O2：2Na2O2+2Cu2++2H2O=4Na++2Cu(OH)2↓+O2↑