Many nations have promised to reduce greenhouse gas emissions, but are falling short of the _______ reduction of 25 to 40 percent of 1990 levels.
| A．target | B．option | C．profit | D．refund |
The zoologist is telling the visitors how a horse’s vision differs from ______ of a human.
| A．it | B．one | C．that | D．those |
This book will show the readers ______ can be used in other contexts.
| A．how that they have observed | B．that how they have observed |
| C．how what they have observed | D．that they have observed |
According to a study carried out by an American university, when you eat has ______ on your mood as ______ you eat.
| A．much of as an effect; what | B．much of as an effect; which |
| C．as much of an effect; what | D．as much of an effect; which |
The first decade of the 21st century ______ breathtaking, non-stop development in China.
| A．witnesses | B．witnessed | C．will witness | D．had witnessed |
The real-name policy for train tickets has been applied to all trains since January 1,2012 in China, ______ I think will make it easy for people to get tickets.
| A．which | B．when | C．what | D．where |