A red sky in the morning ______ to be a sign of bad weather.
| A．says | B．is saying |
| C．has said | D．is said |
The nutrients in _____falls into the ocean quickly become available to other living creatures.
| A．whatever | B．whichever | C．that | D．wherever |
Don’t forget where the emergency exits are _____an emergency.
| A．in place of | B．in favor of | C．in case of | D．in charge of |
The lake is calm and clear, and one of the things that _____in the water is the famous tower.
| A．reflects | B．reflect | C．is reflected | D．are reflected |
The roommates have lived for three years and not once _____with each other.
| A．they had quarreled | B．they have quarreled |
| C．have they quarreled | D．had they quarreled |
My hometown, _____I spent my happy childhood, has changed a lot.
| A．when | B．where | C．which | D．since |