几道英语情态动词的题目1Those who need tickets,please search our website

几道英语情态动词的题目
1Those who need tickets,please search our website to order,or the regular ticketing agents___ be able to sell you.
Awould Bshould Cmight Dcould
2Don't worry,sir!All payments___be made by the end of the month.
AoughtBshallCcanDmust
3.I was thinking of going to see John when who ____ appear but John himself!
Ashall Bshould CwillDmust
4We must apply what we have learned to our daily work because in no case ___ from practice.
Ashould theory separate Bshould theory be separated Ctheory should separate Dtheory should be separated