Question

to drive out foreign influences, the main thing the boxers did was to
recruit members openly.
oppose any kind of immigration.
force closure of all the ports in china.
kill foreigners, missionaries, and chinese christians.

Explanation:

The Boxers, also known as the Yihetuan, were a secret - society movement in China that aimed to expel foreign influence. They carried out violent attacks against foreigners, Christian missionaries, and Chinese Christians as a means to resist foreign encroachment. Recruiting members openly was not their main method for driving out foreign influence. Their focus was not on opposing all immigration in a general sense, nor was it on forcing the closure of all ports in China. Their main violent actions were directed at those they saw as representing foreign and foreign - influenced elements.

Answer:

kill foreigners, missionaries, and Chinese Christians.