Excise C: Listen to some extracts from the dialogue and complete the following sentences with the missing words. Ken: He came on, took off his cloak and shoes, got into a silver ball and curled up. Then his assistant fastened it and pushed it onto the track. Driver: There was probably a moving chain or something. Ken: No, it lokked just like a 1________ — about four meters high. Driver: But how can a ball 2______ a slope? Ken: It must be something to do with the 3________.