1 . Life is full of special moments that deserve to be preserved in photos. If you’re going to the beach, a waterproof camera will help you do that. A waterproof camera is an ideal tool for capturing diving memories and moments of deep sea-fishing trips. Besides, it works equally well for water park visits.    1    

As with any camera, you can choose a waterproof camera with a viewing screen that allows you to see the photos you are lining up or have just taken.    2    For clear viewing in any situation, a waterproof camera with a high-resolution LCD viewing screen is better.

    3    In most cases, you’ll want the smallest and lightest camera you can find. Look for a waterproof camera that weighs 140g or less. In terms of size, choose a waterproof camera that’s no more than two-and-a-half inches in length, two inches in width, and one-and-a-half inches in height so it’s easy to carry around.

It is a good idea to read reviews of the camera carefully and thoroughly before buying a water-resistant camera. Reviews can give people an idea of the kind of settings where the camera can be used and how well the camera performs.     4    If the complaints are about the company’s negative response to quality problems, they can be useful information as well.

If you’re using a waterproof camera underwater, try to get as close to your subject as possible. You’d better take it with you all the time.     5    It could raise the camera’s operating temperature and cause damage.

A．The size and weight of your waterproof camera matter.

B．Some waterproof cameras have a voice control feature.

C．Here is some advice on how to choose and use such cameras.

D．It is because water will absorb warm colors like orange and red.

E．You also need to take special note of any statement of dissatisfaction.

F．Meanwhile, do not leave a waterproof camera in direct sunlight for long.

G．The screen should be clear enough to see underwater or in direct sunlight.

2 . Livestreaming (直播) through channels such as Amazon Live and QVC is an increasingly popular way to sell goods online. It usually lasts between 5 and 10 minutes, and someone promotes a product. Viewers can then readily buy it by clicking on a link.

We analyzed 99,451 sales cases on a livestream selling platform and matched them with actual sales cases. In terms of time, that is equal to over 2 million 30-second television advertisements.

To determine the emotional (情绪的) expression of the salesperson, we used two deep learning models: a face model and an emotion model. The face model discovers the presence or absence of a face in a frame (镜头) of a video stream. The emotion model then determines the probability that a face is exhibiting any of the six basic human emotions: happiness, sadness, surprise, anger, fear or disgust. For example, smiling signals a high probability of happiness, while an off-putting expression usually points toward anger.

We wanted to see the effect of emotions expressed at different times in the sales cases so we counted probabilities for each emotion for all 62 million frames in our database. We then combined these probabilities with other possible aspects that might drive sales—such as price and product characteristics—to judge the effect of emotion.

We found that, perhaps unsurprisingly, when salespeople show more negative emotions-such as anger and disgust—the volume of sales went down. But we also found that a similar thing happened when the salespeople show high levels of positive emotions, such as happiness or surprise.

A likely explanation, based on our research, is that smiling can be unpleasant because it lacks true feelings and can reduce trust in the seller. A seller’s happiness may be taken as a sign that the seller is gaining interests at the customer’s expense.

1. What can we know about the livestreaming in the first paragraph?

A．It damages the physical economy.

B．It helps to sell the products abroad.

C．It helps big companies promote all goods.

D．It is very convenient for the buyers to buy goods.

2. How did the researchers get the findings?

A．By analyzing previous data.	B．By referring to a theory.
C．By giving some examples.	D．By concluding different views

3. What does the underlined word “off-putting” mean in paragraph 3?

A．Surprising.

B．Delighting.

C．Displeasing.

D．Embarrassing.

4. Which of the following could be the best title for the text?

A．Livestreamers Sell Products Successfully

B．Expressions Affect Selling Products Online

C．Emotions and Faces: What’s the Difference

D．Smiling Can Increase the Sales in Reality