to begin to feel uncertain or unsure
开始感到不确定或不安全
"After a few failures, doubt began to creep in."
"经过几次失败后，怀疑开始涌现。"
to remain behind or hesitate to act
to discuss a problem thoroughly to find a solution
someone who is very energetic and determined to succeed
to go beyond the usual limits; to innovate boldly
to swear that something is true, often said with sincerity
to betray someone for personal gain
