One effective access for Chinese leaning is to learn on the internet. During the process when you study Mandarin online, you may often see the phrase开什么玩笑. Usually, when Chinese people use this phrase, they mean to disagree fully with what the others have said or it is impossible to meet the demands of the other party. Here is a dialogue. 甲：对方要求和我们五五分成。乙：开什么玩笑！咱们的付出比他们多多了，你跟他们说最好三七开！
Besides, you should know it is often used to refuse and sometimes it is ironical. Here is an example as reference. 甲：那个学校说只要一年付十万块钱学费，保证你想上哪个大学都行。乙：开什么玩笑！要真是这样，给钱就行了，还学什么！Sometimes, the learners may feel confused when seeing the sentences with 看at the beginning like看谁帮得了你. As a matter of fact, the structure 看… is used to indicate somebody can’t bear a certain serious consequence.
Generally, the foreign students who learn Chinese in China should know that the second person or the third person plus a clause with interrogative words are put after看. Before you use this expression, you should realize that it carries the tone of warning. For instance, 这回咱们有充分的证据，跟他当面谈，看她怎么说！If the learners understand the meaning and usage of such expression, they will get easier in communicating with Chinese people.
If you intend to do something perfect but you need to depend on someone else, the structure看…的了is helpful to express your meaning. When you study in Mandarin learning courses, Chinese teachers may tell you that it indicates to place the hope of doing something perfectly on somebody. It usually collocates with nouns related to persons or pronouns. For instance, 甲：我认识好多大学生，我帮你找一个辅导吧。乙：那就看你的了。