根据对话情景,在空白处填入合适的句子.

根据对话情景,在空白处填入合适的句子.
A：Hello, Michael. This is Kangkang speaking. 21.Would you like to go hiking with me?
B：I’d love to, but I’m afraid I’ll have to go to the library.
A：22. When do you have free time?
B：I think I’ll be free next Saturday. Let’s go hiking then.
A：23. _____________________?
B：Let’s make it half past six.
A：24. _____________________?
B：At the school gate.
A：OK, 25. _____________________.
B：See you.