be pessimistic

( There is) no reason to be pessimistic about the future.

（根本）没有理由对未来悲观。

There is no reason to be pessimistic about the future.

没有理由对未来悲观.

Sometime they can be pessimistic which is caused by their dualistic nature.

由于具双重性格,有时候他们可能会悲观厌世.

In addition to the pessimistic image of the evil nature of humans, Huntington is usually considered to be held by the conservative views of theorists.

除了性恶论的悲观形象，亨廷顿也通常被认为是持有保守观点的理论家。

However, we need not to be pessimistic about it.

但是, 我们不必为此悲观.

However, that "no" comes with this caveat: If you use a CM solution that effectively supports a pessimistic locking scheme, then physical partitioning can be a way to avoid merges.

然而，这个“不可以”中也包括如下这层含义：如果您使用一个能够有效地支持锁定安排的CM解决方案的话，那么物理划分就能够作为避免合并的一种手段。

Don't be pessimistic and discouraged when you meet with difficulties.

遇到困难不要悲观气馁.