挺身而出 [- - ér chū]step forward bravely [boldly]; bell the cat; bolster oneself up; come forward courageously; come out boldly; stand up and volunteer to help; throw oneself forward; thrust oneself forward to face a challenge:
•¶ 他挺身而出， 在大庭广众面前， 慷慨激昂地讲了一通。 He got up in front of the huge crowd and made a moving and fiery speech.