to join with others in giving (help, money, ideas, suggestions etc)

donate, provide

to work or act together in order to bring about a result

aid, assist

to (agree to) pay (a sum of money) regularly (to a cause, for something)

pay for use; contribute

to make oneself responsible for (something); agree, promise, (to do something)

attempt, engage in

of undertake

attempt, engage in

to walk with an effort (across a stream, through water, mud or anything that makes progress difficult)

plod, often through water