Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each question.

Ever since humans have inhabited the earth, they have made use of various forms of communication. Generally, this expression of thoughts and feelings has been in the form of oral speech. When there is a language barrier, communication is accomplished through sign language in which motions stand for letters, words, and ideas. Tourists, the deaf, and the mute have had to resort to this form of expression. Many of these symbols of whole words are very picturesque and exact and can be used internationally, spelling, however, cannot.

Body language transmits ideas or thoughts by certain actions, either intentionally or unintentionally. A wink can be a way of flirting or indicating that the party is only joking. A nod signifies approval, while shaking the head indicates a negative reaction.

Other forms of nonlinguistic language can be found in Braille (a system of raised dots read with the fingertips), signal flags, Morse code, and smoke signals. Road maps and picture signs also guide, warm, and instruct people. While verbalization is most common form of language, other systems and techniques also express human thoughts and feelings.

Sign language is said to be very picturesque and exact and can be used internationally EXCEPT for _______ .

A. spelling

B. ideas

C. whole words

D. expressions

Kim loại không tan trong dung dịch HNO3 đặc nguội là

A. Mg

B. Fe.

C. Ag

D. Cu

a) 

+) Xét \(\Delta\)AMN vuông tại M có:

A + N = 90⁰ (định lí tổng 2 góc nhọn trong 1 tam giác vuông)

=> 60⁰ + N = 90⁰

=> N = 30⁰

Vậy N = 30⁰

b)

+) Xét \(\Delta\)MNH vuông tại H có:

HMN + N = 90⁰ (định lí tổng 2 góc nhọn trong tam giác vuông)

=> HMN + 30⁰ = 90⁰

=> HMN = 60⁰

Vậy HMN = 60⁰

Bài này vận dụng định lí tổng 2 góc nhọn trong 1 tam giác vuông(trong tam giác vuông, tổng 2 góc nhọn bằng 90⁰)

Chúc bạn học tốt! 

Vùng có số lượng đô thị ít nhất của nước ta là

A. Trung du miền núi Bắc Bộ

B. Đông Nam Bộ

C. Tây Nguyên

D. Bắc Trung Bộ

Hoàng đi được:

   34 : 1 x 24 = 816 (km/24 giờ)

       ĐS : 816 km/24 giờ