The 'join in' group
These verbs are concerned with getting involved in an activity or situation. The activity or situation must usually have been mentioned or indicated.
help come in help out join in join up jump in move in stand in step in
She got up to prepare supper. 'Can I help?' asked Polly.
Since everyone else is hell bent on getting fit, I might as well join in.
Those who were fit and of fighting age hurried to join up.
People were asking him to step in and save the country.