These are the correct answers of the exercise:

Incident Comment Incident Comment
Falling under a moving train Thankfully rare but very serious Getting stung by a wasp Common and can be serious in rare cases
Slipping on wet floor Common but usually minor Falling downstairs Rare and often serious
Falling out of a second-floor window Rare but very serious Cutting yourself on a pair of scissors Quite common and minor
Choking on your food Common but usually minor Drowning in a swimming pool Rare but very serious
Breaking your leg in a volleyball game Rare but serious Being mugged on the street Rare but serious