难保的英文：
to be difficult to protect
difficult to protect

参考例句：

Riches have wings
财富难保

You can't say for sure that it won't rain tomorrow.
明天难保不下雨。

There are so many good new actors around that the older ones will soon have to look to their laurels
新演员人才辈出, 老演员不久就地位难保了

By informing on the gang,he was signing his own death-warrant.
他告发了那帮歹徒,自己的性命也就难保了.

"Because, after nightfall, you are not safe fifty yards from the gates."
“因为在天黑以后，出了城门五十码以外就难保安全了。”

difficult是什么意思：
adj. 困难的；执拗的；不易相处的

The exercise is that difficult!
练习题那么难！

You must admit the task to be difficult [ that the task is difficult ].
你应当承认这项任务是艰巨的。

You must admit the task to be difficult [that the task is difficult].
你必须承认这项任务是困难的。

This is as difficult a problem as you are likely to meet.
像这样的难题，你可能会碰到。

Russian is a difficult language to master.
俄语是门难以精通的语言。

protect是什么意思：
v. 保护，保卫

A protective overlay, as for a mattress or furniture.
护套保护性的饰布，如坐垫或家具。

a protective case for a knife or sword.
刀或剑上的保护性外壳。

invoke the protection of...
祈求…的庇护

A protective covering or sheath.
鞘一种保护性的覆盖物或套。

The rights of the people are protected by law.
人们的权益是受法律保护的。