Modal Verbs.

➤1. Complete the sentences using must, have to, should:

I forget to take my key with me. I'll put them here so that I remember them

➤2.Complete the sentences using must, have to, should:

I can’t meet you for lunch because I go to a business meeting at 1:00.

3. I think you walk to and from work instead of taking the bus. Walking is a good exercise.

4. I’ve already finished all my work, so I study tonight. I think I’ll read for a while.

5. Where’s Sue? I talk to her right a way. I have an urgent message for her.

6. I’m very tired. I study last night.

7.You watch TV all the time. You watch TV so much.

➤Во Во Текст во Выберите один ответ:

a. can

b. can have

c. was able to

d. could

➤Во Во Выберите один ответ:

a. can't have

b. wasn't able to

c. could

d. can

e. managed to

➤Во Во Во Во Во Текст во

She teaches English in our school
She doesn't teach English in our school
Does she teach English in our school
She is teaching us to swim now
Is she teaching us to swim?
She isn't teaching us to swim
She will teach him to speak Spanish next year
Will she teach him Spanish?
She won't teach him Spanish
He has breakfast at 8 o'clock every morning
Does he have breakfast at 8?
He doesn't have breakfast at 8
He is having breakfast now
Is he having breakfast?
He isn't having breakfast
He will have breakfast at 9 o'clock tomorrow
Will he have breakfast?
He won't have breakfast
They do homework every day
Do they do homework?
They don't do homework
They are doing homework now
Are they doing homework?
They aren't doing homework
They will do homework in the evening
Will they do homework in the evening?
They won't do homework in the evening

Сначала формулы . затем формулы двойного угла sin2α=2sinαcosα cos2α=cos²α-sin²α=cos²α-(1-cos²α)=2cos²α-1⇒  2cos²α=1+cos2α cos2α=cos²α-sin²α=1-sin²α-sin²α=1-2sin²α⇒  2sin²α=1-cos2α а) сos75°cos105°=cos(90°-15°)·cos(90°+15°)== sin15°(-sin15°)=-sin²15°=-(1-cos30°)/2=(cos30°-1)/2= ((√3/2)-1)/2=0,25√3-0,5б) sin75°sin15°=°sin(90°-15°)sin15°=cos15° sin15°=sin30°/2=1/4=0,25в) sin105°cos15°=sin(180°-75°)cos15°=sin75°cos15°=sin(90°-15°)cos15°=cos15°cos15°=(1+cos30°)/2=(1+(√3/2))/2=0,5 +0,25√3 2 способ формулы cosα·cosβ=0,5cos(α-β)+0,5cos(α+β) sinα·sinβ=0,5cos(α-β)-0,5cos(α+β) sinα·cosβ=0,5sin(α+β)+0,5sin(α-β) а) сos75°cos105°=0,5cos(75°-105°)+0,5cos(75°+105°)=0,5cos(-30°)+0,5 cos180°==0,5· √3/2+0,5·(-1)=0,25√3-0,5б) sin75°sin15°=0,5cos(75°-15°)-0,5cos(75°+15° )=0,5cos60°-0,5 cos90°=0,5·0,5=0,25в) sin105°cos15°=0,5sin(105°+15°)+0,5sin(105°-15°)= =0,5sin120°+0,5sin90°==0,5 sin(180°-60°)+0,5·1=0,5 sin 60°+0,5=0,25√3+0,5