Fill in the blanks with the present continuous and the present perfect continuous tense of the verbs given in brackets.

a. I .............................. (write) this book for the last one year. I ​.............................. (go) to submit it by the end of this month.

b. Surita ​.............................. (suffer) from flu. She ​.............................. (not come) to school since last Monday.

c. Halima ​.............................. (try) to catch up with the mathematics problems. Our teacher ​.............................. (help) her every day after class since last month.