Please choose the correct ending to complete the given sentence: Travel: [header] How to cross a railroad crossing [title] Approach with caution. [step] There should be signs to warn you that you are nearing railroad tracks. Typically, it will be a circular sign with a black x and the letters rr.

Ending1: Once you get closer, you will probably see an x shaped sign that says railroad crossing. On the road, there will be another warning that looks similar to the circular sign. Ending2: It is important to walk slowly and take caution. [title] Press the " up " button on your springboard. Ending3: Tw stands for " easy to pass, " because the train does not directly travel from the railroad track to the railroad station. When you park by this sign, look at the printed word " pass. Ending4: [title] Turn left and make a right turn. [step] The signage will tell you where you need to turn.

Answer format: ending1/ending2/ending3/ending4