简述乳糖。
参考答案：
是半乳糖以β-1，4糖苷键与葡萄糖结合而成的一种还原性双糖，主要存在哺乳动物乳中。
从A-E五个选项中，选出能与下列各句正确匹配的答语。
A. Sure! You're welcome.
B. See you later.
C. With pleasure.
D. Thank you.
E. OK!
( )1. Happy birthday to you!
( )2. Shall we have supper at six?
( )3. Can I go with you , too?
( )4. Could you look after her for me?
( )5. Goodbye!
光绪的谥号是“（）”。
