按收货人抬头，提单可分为记名提单、不记名提单、指示提单。不可以背书转让的提单是（）。
A.记名提单
B.不记名提单
C.空白提单
D.指示提单
正确答案是A
Complete the following sentence with a (compound) word derived from the one given in bracket.
So many people exhaust their health gaining wealth, and then have to spend their wealth to（ ）their health. (gain)
