Q1 The event cannot be deduced from probability.
An event with zero probability is not necessarily an impossible event?
Probability problems are divided into classical probabilities and set probabilities. In the classical probabilities, impossible events and events with zero probability are mutually sufficient. In the geometric probabilities, the probability of impossible events must be zero, but the probability Zero events are not necessarily impossible events. For example: select 1 to 5 on the X-axis, take any point from it, what is the probability of getting point 3. The probability is zero (there are infinite numbers between 1 and 5, i.e. the denominator is infinity and the numerator is 1), but it happens. Regarding the reason, I personally think that there is a big difference between the classical probability and the geometric probability. The probability condition is indeterminate and infinite, unless you can find an element and define it as the smallest division unit, but obviously it's hard because on the number line, numbers are dense and cannot be divided.