Cho (O;R) dây BC, A di động trên cung lớn BC sao cho O nằm trong tam giác ABC, AD,BE,CF lần lượt là đường cao cắt nhau tại H

a) c/m tứ giác ABDE nt, tứ giac EHDC nội tiếp

b) chứng minh tam giác AEF đồng dạng với tam giác ABC

It wasn't a good idea for you to delete that file

-> you.................that file (SHOULD)

1. The man who (televise)...............yesterday is the principal of our shool

2. They (get)........... married, but in the end they changed their mind

3. The speed limit is 30 miles an hour but Tom is driving at 50. He shouldn't (be)............ driving so fast

4. We............ (permit)....................(bring) guests to the ceremony?

1.'' You can't go to David's house until you've done your homework'', Father told James

-> Father refused..............................................................

2.Perhaps Miss Bra was the person who spoke to you

->It....................................................................

3.I'm afraid we've run out of coffee

-> I'm afraid there..........................................

4. Marion was unable to go to the party because she had such a lot of work

-> Marion had so...........................

5. Thousands of people were unable to get to work because of the bad weather

-> The bad weather................................................................

6. It's a waste of time mending that old pullover

-> That old pullover is not.......................................

7. It wasn't until I was 16 that I learned to swim

-> I only.................................................

8. Ray didn't recover from his illness for several months

-> It took..............................................

9.I would prefer you not to smoke in my house

-> I would rather..................................

10. It's such a pity that you couldn't come to our party

-> I wish..................................................

X. Complete the sentences below using the provided words and phrases

1. Albert Einstein/ born/ 1897/ Germany/die/ 1955

2. He/graduate/University of Zurich/1905

3. 1919/win/the Nobel Prize/physics

4. 1919/to 1933/live/Germany/travel/lot/talk/scientists

5.1933/leave/Germany/United States/live/until/death

Khi nói về peptit và protein, phát biểu nào sau đây là sai ?

A. Một số protein tan trong nước tạo thành dung dịch keo.

B. Trong protein không chứa nguyên tố nitơ.

C. Liên kết của nhóm CO với nhóm NH giữa hai đơn vị α-amino axit gọi là liên kết peptit.

D. Thủy phân hoàn toàn protein đơn giản thu được các α-amino axit.