Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions from 31 to 36.

        One of the greatest security threats in the online world is computer hacking. Hackers are people who illegally enter systems. They may alter or delete information, steal private information, or spread viruses that can damage or destroy files. But how exactly can a hacker get into a system to do these things?

        Most hackers use information called protocols that are built into computer software. These protocols allow computers to interact with one another. Protocols are sort of like computer police officers. When a computer connects to another system, the protocols check to see if the access is valid. The protocols can also determine how much information can be shared between the two systems. Hackers can manipulate the protocols to get unlimited access to a computer system.

        In fact, just the act of entering a computer network is commonly considered passive hacking. Passive hackers get a rush from just being able to access a challenging system like a bank or military network. Another kind of hacker tries to do damage to a system. After hacking into systems, these hackers release viruses or alter, delete, or take information. Known as active hackers, they are the more dangerous of the two.

        The easiest way to protect a system is with a good password. Long and unusual passwords are harder for hackers to guess. For even greater security, some online services now use “password-plus” systems. In this case, users first put in a password and then put in a second code that changes after the user accesses the site. Users either have special cards or devices that show them new code to use the next time. Even if a hacker steals the password, they won’t have the code. Or if the hacker somehow gets the code, they still don’t know the password.

Question 31.What should be the main title of the passage?

A. Hackers and Computer Security    B. Funny Things Hackers Do

C. Famous Hackers                D. Good Ways to Stop Hackers

Question 32. The word "threats" in paragraph 1 is CLOSEST in meaning to ____________.
A. danger        B. safety          C. solution      D. benefit

Question 33. What do hackers do to get into a computer?

A. manipulating its codes                   B. replacing security programs

C. making a new password                D. spreading viruses

Question 34. Which of the following can NOT be inferred about active hackers?

A. They make use of the hacked information.           B. They deactivate the protocols in computers.

C. They are more warning than passive ones.            D. They take over the computers systematically

Question 35. What is the easiest way to protect a system?

A. Using a long and unusual password          B. Avoiding online services

C. Sharing passwords             D. Using the same password everywhere

Question 36. The word "assesses” in paragraph 4 is OPPOSITE in meaning to ____________.

A. designs       B. forgets        C. ignores       D. invents

Cho phương trình x2 - 2mx - 1 = 0 (m là tham số)
a) Giải phương trình với m = -3.
b) Chứng minh rằng phương trình luôn có hai nghiệm phân biệt.

Viết phần mở đoạn cho đề cảm nhận về bài thơ " Bài thơ về tiểu đội xe không kính " 

và viết phần cảm nhận về nghệ thuật.

cho tam giác ABC vuông góc tại A có AB=6 , AC=8 , AI là đường phân giác
a, tính BC, IC , IB.
b, kẻ IH vuông góc với AC . Tính IH

Treo một vật nhỏ vào lực kế theo phương thẳng đứng. Nếu để vật trong không khí thì lực kế chỉ F1 = 20 N, nếu nhúng vật chìm hoàn toàn trong nước thì lực kế chỉ F2 = 17,5 N. Cho khối lượng riêng của nước là 1000 kg/m3. Tính độ lớn của lực đẩy Archimedes và thể tích của vật đó.