Bats are surprisingly long-lived creatures, some ______ a life span of around 20 years.
| A．having | B．had | C．have | D．to have |
Mary is being punished by the teacher. That is _______ she broke the school rules.
| A．why | B．because of |
| C．the reason why | D．because |
By improving reading skills, you can read faster and understand more of ______ you read.
| A．that | B．which | C．what | D．how |
----That is ________ you spent your summer holiday, isn’t it?
---- That’s right.
| A．where | B．which | C．what | D．if |
Human beings are different from animals _________ they have languages.
| A．where | B．in that |
| C．in which | D．for which |
At school, some students are active, ______ some are shy, yet they can be good friends with one another.
| A．while | B．although | C．since | D．thus |