In fact, they're just there as back up.

重申一下,课本就是救命稻草

耶鲁公开课 - 博弈论课程节选

People are saying stem cells are basically going to be the new miracle drug.

人们常说干细胞将会是新的救命的奇药。

关于干细胞的研究 - SpeakingMax英语口语达人

I regard these books as safety nets.

课本只不过是救命稻草

耶鲁公开课 - 博弈论课程节选