Really need a help

can someone please help me solve this drill?

there's a schema:

ACTIVITY_TYPE (Activity_type_code, Activity_type)
USERS (User_code, User_name, Password)
PROJECT (Project_code, Project_name, Customer_code, Cost, Start_date, End_date)
CUSTOMER (Customer_code, Customer_name)
ACTIVITY (Activity_code, Activity_name, Project_code, Activity_type_code, Complexity)
ACTIVITY_IMPORTANCE (Customer_code, Activity_code, importance)
CREATED_BY (Activity_code, User_code)
ASSIGNED_TO (Activity_code, Developer_name)
DEVELOPER (Developer_name, Seniority)
NEEDED_PARTS (Activity_code, PartID, cost)

and i need to return (in RA) all activities (from (activity_name)) and projects names who belonged to them that meet to following requirtements:

1. high complexity
2.the customer who ordered a project payed for each of the projects he ordered at least 100k
3.at least some of the project's building time was on april 2012

thank you very much!! the help is much needed