Susan ________Tina are good friends.
句意：苏珊和蒂娜是好朋友。
考查连词辨析。or或者，表选择；and和，表等同关系；but但是，表转折。“苏珊”和“蒂娜”是等同关系，在句中作并列主语，故应用and连接。故选B。
Susan ________Tina are good friends.
Miss Zhao is very helpful. She often helps us ____we are in trouble.
He was so tired that he fell asleep ___he went to bed.
—Which book do you prefer, Harry Potter or Treasure Island?
—Harry Potter, of course, ____I ___ my sister likes it.
Millie’s research paper isn’t up to standard______ she has worked at it for two weeks.
—Don't forget to protect your eyes well______ you take online classes.
—OK. Thank you, Sir.
_____ the outbreak of COVID-19 is a terrible blow to the country, the government is trying hard to bring the situation under control.
_______ you have problems, just let me know. I'll always be there for you.
We should protect the environment _______ we can make a better world to live in.
____ she is very young, she can take good care of herself.
