[单项选择]What is the main problem caused by the usual way of plowing
A．The crop’s blooming period is delayed.
B．The roots of crops are cut off.
C．The top soil is seriously damaged.
D．The growth of weeds is accelerated.

[单项选择]What caused the problem
A. A bad weather
B. A defective product
C. A delivery charge
D. A supply shortage

[简答题]What language skills are emphasized and what main techniques are used in the Direct Method classroom

[单项选择]What main role do the staff play in the school restaurant
A. They make sure that students eat their meals in time.
B. They deal with students’ complaints about the food.
C. They help students learn about a balanced diet.

[填空题]The usual way Americans signal their attention to their talking partners is to look at their eyes or mouths.

[判断题]

The vapor problem was mainly caused by the chemical containments from the ground- water out of the company.

[单项选择]What is the main idea of the news

What is the main idea of the news
A．Benigno Aquino won the election.
B．Mrs. Arroyo was accused of corruption.
C．Benigno Aquino took the oath of office of president.
D．Benigno Aquino will immediately form an independent commission to investigate
corruption allegations against Mrs. Arroyo.
A. Benigno Aquino won the election.
B. Mrs. Arroyo was accused of corruption.
C. Benigno Aquino took the oath of office of president.
D. Benigno Aquino will immediately form an independent commission to investigate corruption allegations against Mrs. Arroyo.

[单项选择]

The usual way to ensure reliable delivery is to provide the (20) with some feedback about what is happening at the other end of the line. Typically, the protocol calls for the receiver to send back special (21) flame bearing positive or negative (22) about the incoming frames. If the sender receives a positive acknowledgement about a frame, it knows the frame has arrived safely. On the other hand, a negative acknowledgement means that’ something has gone wrong, and the frame must be transmitted again.
An additional complication comes from the possibility that hardware troubles may cause a flame to (23) completely. In this case, the receiver will not react at all, since it has no any reason to react. It should be clear that a protocol in which the sender transmits a frame and then waits for an acknowledgement, positive or negative, will hang forever if a frame is ever lost due to, for example, (24) hardware.

（22）是（）
A. application
B. connection
C. stream
D. acknowledgement