此句不完整,我看到的原句在humble 前还应有一个how .即:
It shoud be remembered how many failures and defeats marked his early life
and how humble and unpromising his early beginings were.
分析句子结构及成分如下:
It shoud be remembered 是主句,其中it 作形式主语.
how many failures and defeats marked his early life (主从1)+and +(主从2) how humble and
unpromising his early beginings were.是由and连接的两个并列的主语从句作主语.
how many failures and defeats(主语)+ marked(谓动,意为"笼罩" ) + his early life (宾语).
how humble and unpromising(表语)+ his early beginings(主语)+ were(系词)
句意:有一点必须记住：他早年的生涯中充满了失败和挫折,
而且他的人生初期是多么的卑微、前途黯淡.
或译成:应该被记住的是:他早年的生活中有多少的失败和挫折,
而且他人生的起步是多么的卑微无望.