We would like to point out that delivery before Christmas is essential and hope you can offer us that guarantee.
我们想指出圣诞节前交货很重要并希望贵方能就此向我们作出保证。
I'm very sorry. Usually I'm very careful. I have never lost a book before. It won't happen again.
“很对不起。通常我是非常小心的。我以前从来没有丢过书。这样的事不会再发生了。”