题目内容：

SAN FRANCISCO(AP)-Samsung says new Galaxy Note 7 smartphones will be available in U.S. stones starting Wednesday to replace about 1 million devices that are being recalled because their batteries can catch fire.                 The South Korean company has been scrambling to fix problems caused by faulty batteries in the latest version of its top of the line smartphone which first went on sale last month.

When it first offered on Sept. 2 to replace the affected Note 7 phones Samsung said it would swap them for models of its other phones such as the Galaxy S7 until supplies of replacement Note 7 devices became available.

Samsung followed up last week by announcing that U.S. consumers who had purchased one of the recalled phones could choose between a replacement or a refund fro the device which sells for about $850. That offer was jointly announced with officials at the U.S. Consumer Product Safety Commission after Samsung was criticized for not coordinating more closely with the commission.

Safety officials have urged Note 7 owners to turn off their phones and return them immediately. They cited reports of Note 7 batteries overheating in the United States including 26 instances where individuals were burned and 55 that caused property damage.

The problem doesn’t affect all Note 7 phones because Samsung uses batteries from different suppliers. But the company has said about 2.5 million devices may be affected worldwide including 1 million sold in the United States.

Samsung also said it’s pushing out two software updates through wireless carriers. One will show a green battery icon to confirm that a Note 7 device is a new one that doesn’t have the battery problem. The other will display a short notice to owners of older phones covered by the recall telling them to turn off their device and take it in for a replacement.

About a quarter of affected phones had been exchanged in the United States by Tuesday According to a spokeswoman for Samsung’s U.S. subsidiary. She was unable to say how many Note 7 buyers sought refunds but said “the vast majority” received a different Samsung phone as a replacement.

1.What’s wrong with the affected Note 7 phones?

A. The price of them is too high.

B. Their batteries can catch fire.

C. They are similar to iphone 7.

D. They have problems with their earphones.

2.What can a U.S. consumer who had purchased one of the recalled phones do according to Samsung’s announcement?

A. To sell his/her recalled phone to others for about $850.

B. To choose a replacement and a refund for his/her recalled phone.

C. To use the recalled phone to replace a Galaxy S7 first and then one of the new Note 7 devices for free.

D. To return the recalled phone and get a replacement or a refund (about $850) for the device.

3.How many affected phones had been exchanged in the United States by Tuesday?

A. About 0.625 million.

B. About 0.25 million.

C. About 0.875 million.

D. About 1 million.

4.What can we learn from the passage?

A. At least 81 cases of Note 7 batteries overheating were reported in the United States.

B. The Note 7 phones sold in China are safe.

C. The Note 7 phones used batteries from different suppliers never have the  same problems.

D. The Galaxy S7 devices are the safest.