vt.

1. 召唤；传唤；请求；要求[O2]
   He was summoned to appear in court as a witness.

   他被传唤出庭作证。

   He came downstairs and summoned her to his study.

   他下楼将她叫到书房去。

2. 召集
   They had to summon a second conference and change the previous decision.

   他们不得不召集第二次会议，改变以前的决定。

3. 使出，唤起，鼓起（勇气），振作（精神）[（+up）]
   He summoned up his courage and proposed to her.

   他鼓起勇气向她求婚。

v.

1. authoritatively call on (someone) to be present, especially to appear in a law court.
2. call people to attend (a meeting).
3. (usu. summon something up) cause (a quality or reaction) to emerge from within oneself:
   she managed to summon up a smile.