who指的是students,是复数.顺便说一下,如果主句中的one前面有the only,则who就是指he,则谓语部分就要用was了.
因为逗号前面不是一个并列分句,而是一个非谓语短语,这个短语在句中作原因状语.如果改成分句There were no buses,则逗号后面要加一个并列连词and.
climbed in与followed是并列动词作谓语.sword in hand是独立主格结构,表示伴随动作.这个独立主格结构可以改成with的复合结构：with a sword in his hand；或改成一个并列分句：and a sword was in his hand.记住,改成并列分句后一定要加相应的连词,如and,but.
更上一层楼!
不明白的再问我.