TranCeptStay研究的启示是（）

A、to stay

B、to staying

C、stay

D、staying

听力原文：Vinay, this is Nisha. I have your reimbursement form. and receipts for the business dinner you paid for last week. The amount on your form. is $175.55, but the receipts' total is $157.25. Have you written the wrong amount on the form? Or have you forgotten to include one of your receipts? Please call and let me know, so that the accounts can process your request for reimbursement. I'm available on Extension 09 till 5 p.m. Thanks.

What is the purpose of this message?

A．To collect a bill.

B．To return a product.

C．To reserve a table.

D．To get a clarification.

Tourists pay to stay with families.

系统y"(t)+2y'(t)+ay(t)=f(t)的冲激响应为：，则常数a=（）

How does Jerry manage to stay positive?

Why do British women, especially, long to stay young?

They often use text messages to stay in touch with customers.

What stays hot even if put in a refrigerator?