The trouble with these systems is that new viruses are being created all the time at an estimated rate of eight a day and rising so the companies that make antivirus software are forced to play a constant game of catch-up.

• 这些系统的弊端在于，新的病毒在不断地以大约每天8个的速度被创造出来，所以制造反病毒程序的公司就被迫不断更新程序。