[单项选择]Crops can be traded on the futures market before they are harvested. If a poor corn harvest is predicted, prices of corn futures rise; if a bountiful corn harvest is predicted, prices of corn futures fall. This morning meteorologists are predicting much-needed rain for the corn-growing region starting tomorrow. Therefore, since adequate moisture is essential for the current crop’s survival, prices of corn futures will fall sharply today.
Which of the following, if true, most weakens the argument above
A. Corn that does not receive adequate moisture during its critical pollination stage will not produce a bountiful harvest.
B. Futures prices for corn have been fluctuating more dramatically this season than last season.
C. The rain that meteorologists predicted for tomorrow is expected to extend well beyond the corn-growing region.
D. Agriculture experts announced today that a disease that has devastated some of the corn crop will spread widely before the end of the growing season.
E. (E) Most people who trade in corn futures rarely take physical possession of the corn they trade.

[单项选择]Children can speak before they can read or write shows that language is
A. arbitrary.
B. used for communication.
C. productive.
D. basically vocal.

[单项选择]　　　 Long before they can actually speak, babies pay special attention to the speech they 　　　 hear around them. Within the first month of their lives, babies’’ responses to the sound of 　　　 the human voice will be different from their responses to other sorts of auditory stimuli. They will stop crying when they hear a person talking, but not if they hear a bell or the (5)　 sound of a rattle. At first, the sounds that an infant notices might be only those words that 　　　 receive the heaviest emphasis and that often occur at the ends of utterances. By the time 　　　 they are six or seven weeks old, babies can detect the difference between syllables 　　　 pronounced with rising and falling inflections. Very soon, these differences in adult stress 　　　 and intonation can influence babies’’ emotional states and behavior. Long before they (10)　 develop actual language comprehension, babies can sense when an adult is playful or 　　　 angry, attempting to initiate or terminate n
A. How babies differentiate between the sound of the human voice and other sounds
B. The differences between a baby’’s and an adult’’s ability to comprehend language
C. How babies perceive and respond to the human voice in their earliest stages of language development
D. The response of babies to sounds other than the human voice

[单项选择]A. That babies understand language before they can speak.
B. That babies have simple mathematical skills.
C. Babies’ preferences for different kinds of toys.
D. The influence of television on babies.

[单项选择]Before you can hear a message on the telephone using the new system, ______.
A. electrical signals must first be changed into light signals and then into sound
B. the light signals have to be changed directly into sound messages
C. light signals must first be changed into electrical signals and then into sound
D. either the light or the electrical signals have to be changed into sound message

[填空题]Before you can use the Internet, you must choose a way to
move data between the Internet and your PC. This link may be a
high-speed data communication circuit, a local area network
(LAN), a telephone line or a radio channel. Most likely, you will
use a Modem attaching to your telephone line to talk to the 1. ______
Internet. Naturally, the quality of your Internet connection and
service, as many other things in life, is dictated by the amount of 2. ______
money that you are willing to cost. 3. ______
Although all these services can well satisfy the needs of the
users for information exchange, but a definite requirement is 4. ______
needed for the users. Not only should the users know how the 5. ______
resources locate, but also he should know some operating 6. ______
commands concerned to ease t