单项选择题 In stopping distances of vessels，head reach can best be described as the（）.

单项选择题 If you do NOT understand the course or intention of an approaching vessel you should sound （）.

单项选择题 If the PSCO from general impressions or observations on board has（）for believing that the ship，its equipment or its crew do not substantially meet the requirements，the PSCO should proceed to a more detailed inspection.