Young men who have reason to fear that they will be killed in battle may justifiably feel bitter in the thought that they have been cheated of the best things that life has to offer.______

单项选择题But human beings, owing to the length of infancy, find this difficult.______

单项选择题If you have wide and keen interests and activities in which you can still be effective, you will have no reason to think about the merely statistical fact of the number of years you have already lived, still less of the probable brevity of your future.______

A.如果你有广泛的爱好和强烈兴趣并仍然参加活动，你就没有理由去考虑自己活了多大岁数这样的数字，因为你的将来或许还会很长。
B.你要是有广泛的爱好和强烈的兴趣，而且还有能力参加一些活动，你就没有理由去考虑自己已经活了多少岁这样的具体数字，更没有理由去考虑自己的余年大概是很有限的了。
C.你若是有广泛而强烈的爱好，而且仍参加活动，不要去考虑将来的长短，也不要考虑自己活了多少年这样的具体数字。
D.如果你有广泛而强烈的爱好，并能参加活动，你就没有理由去考虑已经活了多少年这样的数字, 更别说自己的余年是否有限。