Use of English 1have to don't have to6.5.13.1 Read the table and the rules.Say the examples in your language.Affirmative1/You have to go.He/She/It has to go.Negative1/You don't have to go.He/She/It doesn't haveto goWe/You/Theyhave to goWe/You/They don't haveto go.We use have/has to to express obligation, I have to take my medicine. (The doctor told me.)We use don'tdoesn't have to to expresslackof obligation. You don't have to go to the gymto exercise. (It's not necessary.)​

1-Has he developed a new design of this machine?
2-Will she have written the report by Monday?
3-Is she conducting the experiment?
4-I don't use computers in my work
5-He was doing the calculations when the professor came.
6-Will you test your construction next week?
7-Had she left the laboratory before the work was finished?
8-Is your theory based on careful observations?
9-Should you start your work at laboratory in the morning?
10-We cant control this research without a computer.
11-Didnt we solve the problem two days ago? Или We didn't solve the problem two days ago. (Смотря если вопрос или отрицательное предложение)
12- She doesn't apply new methods of calculations.

1-Has he developed a new design of this machine?
2-Will she have written the report by Monday?
3-Is she conducting the experiment?
4-I don't use computers in my work
5-He was doing the calculations when the professor came.
6-Will you test your construction next week?
7-Had she left the laboratory before the work was finished?
8-Is your theory based on careful observations?
9-Should you start your work at laboratory in the morning?
10-We cant control this research without a computer.
11-Didnt we solve the problem two days ago? Или We didn't solve the problem two days ago. (Смотря если вопрос или отрицательное предложение)
12- She doesn't apply new methods of calculations.