抱佛腳

(fig.) to scramble to make up for a lack of preparation; to make a frantic, last-ditch effort; to cram for an exam (cf. 平時不燒香，臨時抱佛腳|平时不烧香，临时抱佛脚[ping2 shi2 bu4 shao1 xiang1 , lin2 shi2 bao4 fo2 jiao3])