"Chinese" is the correct adjectival form, the "toponym" meaning "from China," so in 1 and 2 the first forms are more correct. Why do I say "more correct?" Because in English, there is a strong tradition of using nouns as adjectives. Sometimes this can be completely correct, usually it is informal. "A China company" or "A China phone number" are incorrect and would be heard as incorrect, but would be understood. A native speaker might even say them. People who like to be careful about their English wince when we hear things like "a fry pan" instead of "a frying pan," or "a driver license" instead of "a driver's license," but it is often legitimate, and there are grey areas. For example, there is a color name, "China red," for a certain shade of red that is a little orangey. It seems as if it ought to be "Chinese red," but that's wrong and would confuse people--the name of the color is "China red." I can't give you any logical explanation, but you "close" a bank account and you "cancel" a credit card. Usually "cancel" means you're stopping something that's happening or about to happening. You cancel a commitment, a promise, an appointment. "I had to cancel my doctor's appointment." You cancel a magazine subscription. "Hello, Springfield Fitness Center? I'd like to cancel my membership. I paid in advance through December, will you refund my membership fees for those months?" "Terminate" is fairly formal. "Terminate" a credit card or a bank account are acceptable English and would be understood, but that isn't the customary word to use.

1. A Chinese company. An American company. While nouns can often be used as adjectives (car keys, dog collar), if there is an adjective (Chinese, American), the adjective is the correct choice. 2. A Chinese phone number. An American phone number. See my answer to #1. Same situation. 3. to cancel my phone card. We cancel a card. We close an account. 4. to cancel my bank card. See #3. Same situation.

China is the noun we use for the country whereas Chinese is the adjective we use for things belonging to China such as language, people, etc, and companies as in this sentence. America and United States are nouns, so we need to use the adjective American. However, if we then use the abbreviation 'US' this can be used as an adjective. So: 1. A Chinese company, a U.S. company, an American company - are all correct. 2. A Chinese phone number, a U.S. phone number, an American phone number - are all correct. For sentences 3 and 4, you need to understand the meaning of the three verbs. cancel - abolish, abort, rescind close - to put something in a position to obstruct an entrance, opening, gap to stop things or people coming through terminate - abolish, abort, cancel As you can see, you can use 'cancel' or 'terminate' for sentences 3 and 4. The most common is 'cancel'. However, to confuse you a little more, we use 'close' if we want to 'close a bank account'. This means that we cannot access the account anymore. We can't 'get into the account' anymore.

1. "A Chinese company" is correct.... in this case "China" is a noun so it is not correct to you, but "Chinese" is an adjective so it is the correct answer. You can say both "A U.S. company" or "An American company." 2. Same as #1. 3."To cancel my phone card" would be the preferable way to say this. 4. It is probably best to say "to cancel my bank card." If you are closing the bank account (which would also close your bank card), then you are going to "close the bank account" not "cancel the bank account." The differences are not great.