Talking is the most common way of ____________________ (relax)

Quần xã sinh vật là:

A. Tập hợp các sinh vật cùng loài 

B. Tập hợp các cá thể sinh vật khác loài 

C. Tập hợp các quần thể sinh vật khác loài 

D. Tập hợp toàn bộ các sinh vật trong tự nhiên

Choose the letter A, B, C or D to answer these following questions

The history of the computer in the twentieth century is one of dramatic adaption and expansion. The computer had modest beginnings in areas where it was used as a specialist tool. The first electronic computer was built in the 1930s and was solely for use of undergraduate students in Iowa State University to handle mathematical computations in nuclear physics. In World War II, computers were developed in order to wage counter espionage and break codes used by the enemy. In the post-war years the scope of computers was expanded to include the military industrial complex and academia. Obviously people needed to travel around these institutions and so there was a need for early network tools. In the 1960’s an early version of the Internet, ARPPANET was used in computers were starting to change our lifestyle, the way we do business and many style things (Elliot, 1994) and by the late 1980s, networks were expanding to embrace sections of the general public. The internet was born.

Question:In World War II, computers were developed in order to____________.

A. break enemy’s code

B. call other soldiers

C. do calculations

D. study geography

III. Choose the word with the different stress syllable.

A. statistics     

B. history     

C. concentrate     

D. different

Gọi A là tập hợp các giá trị của x thỏa mãn |x - 17| - |-26| = 30. Tổng các giá trị của A là:

A. −112

B. 34

C. −34

D. 112