英版海图某灯塔灯高49m,额定光力射程25M,已知测者眼高为16m,则能见度良好（）时该灯塔灯光的最大可见距离是

A．操作系统是计算机软件系统中的核心软件

B．操作系统属于应用软件

C．Windows是PC机惟一的操作系统

D．操作系统的5大功能是：启动、打印、显示、文件存取和关机

i n e d p a r t i n e a c h s e n t e n c e w i t hou t c h a n g i n g i t s o r i g i n a l m e a n i n g . 8 . A b i g i n t e rn a t i o n a l b a n k j u s t c a n ’ t a ff o r d t o a li e n a t e c li e n t s i n c o un t r i e s a r o u n d t h e w o r l d

A．s e p a r a t e

B．g i v e u p

C．d i s c a r

D．d i s t a n c e

A．For most Chinese people，the crowds of scenic spots and avenues and city roads during the holidays are the two main reasons for their vacation at home

B．For most Chinese，during holidays and festivals, the scenic spots are full of people,highways, urban road congestion, are the two main reasons to promote their home vacation．

C．For the majority of Chinese people,overcrowded tourist sites,congestion on expressways and city roads during holidays are the two major factors contributing to their staycations．

D．For most Chinese people， during the holidays, there are a large number of people in the scenic area,and the congestion of expressways and urban roads are the two main reasons for their holiday at hom

E．

H＞,＜A,C＞},问这棵树中结点G已知一棵树边的集合为{＜I,M＞,＜I,N＞,＜E,I＞,＜B,E＞,＜B,D＞,＜A,B＞,＜G,J＞,＜G,K＞,＜C,G＞,＜C,F＞,＜H,L＞,＜C,H＞,＜A,C＞},问这棵树中结点G的双亲结点为（）

A．A B

C．I

D．B

A．guarantee

B．ensure

C．bargain

A．湖北省和重庆市

B．北京市和上海市

C．黑龙江省和山西省

D．安徽省和四川省