Use the Present Perfect Continuous. 1. He (play) the piano since 6 o'clock in the morning.
2. It (not rain) all day.
3. Your eyes are red. You (cry)?
4. Farther (read) the newspaper since early morning.
5. His sister (not study) French for 6 years.
6. We (write) our article for a week.​

Alot of factories produce waste and is drained into rivers. so the water in the rivers becomes poisoned. the hole in the ozone layer is very dangerous to humans: ultraviolet radiation passes through them and reaches the ground. such radiation may cause dangerous diseases. the population of many countries is suffering from lack of water. nuclear weapons can produce terrible destruction on our planet. nuclear power plants are not so “clean” as some believe: they become the source of the contamination. the environment is everything you see around you. today people understand the need to keep it clean, if humanity wants to survive.

Time management is the act or process of exercising conscious control over the amount of time spent on specific activities, especially to increase efficiency or productivity. time management may be aided by a range of skills, tools, and techniques used to manage time when accomplishing specific tasks, projects and goals. this set encompasses a wide scope of activities, and these include planning, allocating, setting goals, delegation, analysis of time spent, monitoring, organizing, scheduling, and prioritizing. initially, time management referred to just business or work activities, but eventually the term broadened to include personal activities as well. a time management system is a designed combination of processes, tools, techniques, and methods. usually time management is a necessity in any project development as it determines the project completion time and scope. time management strategies are often associated with the recommendation to set personal goals. these goals are recorded and may be broken down into a project, an action plan, or a simple task list. for individual tasks or for goals, an importance rating may be established, deadlines may be set, and priorities assigned. this process results in a plan with a task list or a schedule or calendar of activities. authors may recommend a daily, weekly, monthly or other planning periods associated with different scope of planning or review. this is done in various ways, as follows. time management also covers how to eliminate tasks that don't provide the individual or organization value.