一、Write the key words or phrases from memory(默写重点单词与词组)10分

1.风景,山水画_________　                              2.包围,围绕_________

3.海湾_________                                                    4.海港_________

5.火山_________                                                   6.泉水_________

7.表面,外表_________                                     8.安家,定居_________

9.占有,财产_________                                     10.同意,一致_________

11.婚宴_________                                           12.埋葬_________

13.会议 _________                                                14.关系,联系_________

15.农业的_________                                              16.牲畜_________

17.海边别墅_________                                    18.航行_________

19.输出,出口 _________                                        20.区域_________

空气中的负离子对人的健康极为有益. 人工产生负离子的最常见方法是电晕放电法．一排针状负极和环形正极之间加上直流高压电，电压达5000 V左右，使空气发生电离，从而产生负一价氧离子排出，使空气清新化，针状负极与环形正极间距为5mm，且视为匀强电场，电场强度为E，电场对负氧离子的作用力为F，则     

A．E=10³ N/C，F=1.6×10^—16 N

B．E =10⁶ N/C，F =1.6×10^—16 N

C．E =10³ N/C，F ="1." 6×10^—13N

D．E =10⁶ N/C，F ="1." 6×10^—13 N