Very little is known about Antarctic killer whales.我们对虎鲸的所知有限

know about:知道； 了解； 听说过有关 ... 的情况

I'd love to know about the plan.

我想知道这个计划。

I happened to know about him.

我正好了解一些他的情况。

assign用法:

1.在美国，assign指“指定（功课）”，而其名词形式assignment则指“被指定的功课”，其后通常跟in

，如an assignment in accounting；

2.注意assign后可加宾语，加to，再加名词或代词。不过习惯上常不用to。

The authorities assigned him to an important task.

他分配到了一个很重要的任务。

The authorities assigned him an important task.
上级给他分配了一个很重要的任务。

Series producer Martha Holmes and cameraman David Baillie were on board节目制作人玛莎霍姆斯和摄影师大卫贝利在飞机上

on board:在船（车或飞机）上

Many of the tourists on board had begun bargaining with the tradesman.

船上的很多旅客开始与商人讨价还价了。

On this trip, some time on one of the helicopters is assigned to the Life team.这一趟行程中，他们将一架直升机指派给“生命脉动”团队

be assigned to:归属于, 被指派

Jack was assigned to the assembly shop of the factory.

杰克被分配到厂里的装配间工作。

All the students are assigned to suitable jobs.

所有的学生都分到了合适的工作。