The failed terror bomb plot constitutes Mr.Obama's most serious national security test to date, and the president has been quick to acknowledge that there is plenty of room for improvement.
VOA : standard.2010.01.06
英汉双解词典包含3185865条英汉词条，基本涵盖了全部常用单词的翻译及用法，是英语学习的有利工具。