百善孝为先。我国历来把“孝”看成是“天之经也,地之义也,民之行也”,因为孝敬父母长辈是①中华民族的传统美德 ②公民必须履行的义务③中华民族精神的核心 ④为人处事的唯一准则
Some researchers believe that there is no doubt _______ a cure for AIDS will be found.
To write his paper, he tried hard to collect _______ information as he could.
Don’t worry. You ________ have that book tomorrow.
Nearly all educators believe that a challenging situation can often _______ the best qualities of a person.
He found his son _______ inside the lift, _______ very worried.