单项选择题 When you are transferring fuel oil to the setting tanks, precautions to be observed should include （）

单项选择题 Heavy fuel oils generally have an upper average ash content of 0~1% by weight.Which of the following conditions could be expected if the ash content increase above this amount?（）

单项选择题 The flash point of a residual fuel oil should be used to determine the highest temperature to which oil may be heated （）