in body/in a body

in body 是指“亲自”，而 in a body 是指“一道”“一齐”“全体一致地”（all together, as a whole）：

1. I observed the incident in body. 我亲自目睹了这件事。

2. The staff resigned in a body. (ALD) 工作人员全体辞职。

3. They marched in a body to the minister's house and demanded to see him. (LDCE) 他们全体走到部长官邸,要求见他。

in care of/in the care of 见 care

in case (of)/in the case of 见 case $^{8}$

in charge/in the charge 见 charge

in collar/in the collar 见 collar

in control of/in the control of 见 control

in course of/in the course of 见 course