Four unrelated fatal stabbings one day last week in London brought to 50 the number of people slain by knife this year in the capital, and of those 20 were teenagers.

• 上星期在伦敦，一天之内分别发生了四起持刀行凶杀人案，这使得伦敦今年死在匕首下的人达到50，其中有20人是青少年。