насторожиться(And always remember that if a plan promises you'll get rich quick with no risk or doesn't tell you how your money will be invested, you should raise a red flag and exercise caution before getting on board. 4uzhoj)
обратить внимание на(Those who voice the most displeasure in their marriage, are more likely to complain about their partner's weight, Newport adds, which may help counselors red-flag weakening relationships before it's too late.Jack the Lad)