letter of guarantee造句

1、Secondly, I probe into the theory of the letter of guarantee and its practical usage.
本文第二部分则对海运保函的理论及在海运实践中运用进行了一些探讨。

2、Are the guests asked me to write a letter of guarantee to him.
现客人要求我写一个保证函给他。

3、The letter of guarantee in the contract before the expiry of the warranty in full force and effect.
本保证函在本合同规定的质保期满前完全有效。