下列各句中，没有语病的一项是

What a nice day! We decide ______ out for a picnic.

Emergency line operators(接线员) must always _____ calm and make sure that they can get all the information they need to send help.

We thought there were 35 students in the dining hall, ______, in fact, there were 40

Do you like the voice of the famous singer— Yes, it ___________ very nice and sweet.