dear experts, 
                      i have answered correct with correct spellings in english tenses activity.but it is showing it incorrect. i have checked it from answer given. and mine is totally correct......
    please help me..............

As checked, your account runs flawlessly at our end. In case, you are using some other browser, we would request you to use either Google Chrome or Mozilla Firefox. Also, clear your cookies, temporary internet files and history, as these are a kind of hindrances in the smooth functioning of the system.

In case the situation still persists, then kindly forward the screen shots of the activities in which you are facing this discrepancy.

Regards,
Abhirup