vái trời 
beseech the god [ vái ] : to greet with clasped hands
[ trời ] : heaven, sky; area, region, sphere
Most Common Compounds Set 1:
Most Common Compounds Set 2 :
cóc vái trời a toad praying to heaven, useless thing to do vái trời beseech the god cóc vái trời a toad praying to heaven, useless thing to do