You can surf the Internet ______ you want to know more about the 2020 World Middle School Games.
句意：如果你想知道更多关于2020年世界中学运动会的信息，你可以上网。
考查连词辨析。if如果，引导条件状语从句；although尽管，引导让步状语从句；until直到……为止，引导时间状语从句。空前讲“你可以上网”，空后讲“你想知道更多关于2020年世界中学运动会的信息”，空后是空前动作进行的条件，用if引导条件状语从句。故选A。
You can surf the Internet ______ you want to know more about the 2020 World Middle School Games.
—How time flies! The middle school life is coming to an end.
—Yes. We have to say goodbye, ________ our friendship will last forever.
Mike and Jim's room is tidy, ______ their sister's not.
Our English teacher is nice and patient she is very strict with us.
Even if we learn something well, we will forget it ______ we use it.
Wash your hands before meals, ______ you may get ill.
—Who went to the graduation party last night, Mary?
—Almost everyone did. ______ lots of students _____ Ms. Wang appeared at the party.
Restaurants must stop offering free plastic bags in Beijing _______ customers ask for them.
—Tim, our foreign teacher Ms. Green will go back to England next week.
—Really? Let's have a party to say goodbye to her ______ she is free this weekend.
______ you keep moving, you'll never reach the top of the mountain.
