this is our last chance,so we cannot---to experience another

选 afford [这是我们最后一次机会了,所以我们承担不起再一次失败了.]
因为 afford to do sth.(承担得起,担当得起) 符合题意.
而 bear常用于 bear doing sth.,虽然也可bear to do sth.但表达的意思是“容忍”,与题意不符.