Must wear a helmet的意思|示意

On a bike you must wear a helmet.

在骑自行车的时候，请你戴上头盔。

Entering the site must wear a helmet.

进入工地现场，必须佩带安全帽。

All the competitors must supply their own safety equipment and must wear a helmet. Gas and electric powered bikes are not permitted.

参赛者自备参赛车辆、装备与护具，所有车辆不得配有任何非人力传动、助动装置。

Performing under the name Jaimi Starr, she cannot wear a helmet as this would affect the drag and she must keep a constant speed to beat the gravity that would otherwise pull her down.

泰利尔的艺名是贾米斯塔尔，在演出过程中她不能戴头盔，因为这可能会影响骑行。在骑行过程中她必须保持恒速前进，才能够克服重力不掉下来。

Riderss must wear a full face helmet (either fixed or detachable) at all times during the race including liaison stages on the bike.

车手在比赛期间必须佩戴全盔(固定式和可拆分式)，包括骑车通过的转移路段在内。

All participants must wear a safety helmet or bike helmet during the race.

所有参赛者必须佩戴安全帽或单车头盔进行比赛。