先秦和秦汉文学中常出现“关”和“山”，如“关中”、“山东”等。这里“关”和“山”分别指哪那道关和哪座山（ ）

Hillary Clinton arrived in Pyongyang on August 4, 2009, ______ the start of the short visit to Korea. [ ]

________for her，Chen Zhong，the last champion，had no chance to take part in the finals

___ pen is red and ___ is red, too.

Though the novel had a happy ending, the readers were left ____.