The 20^th World Cup will be held in Brazil ________ June 12 ________ July 13, 2014．

A．in：to

B．in：to

C．at：from

D．from：to

Cars make our life easier, ________ they bring environment problems．

A．as

B．or

C．but

D．so

The Chinese ________ Mo Yan won the 2012 Nobel Prize in literature (文學(xué)), and it cheers us up．

A．artist

B．scientist

C．writer

D．singer

The teacher is wise enough to explain the most difficult questions in ________ way．

A．simple

B．simpler

C．the simplest

The huge yellow rubber duck ________ to 13 cities in 9 countries since 2007．

A．travels

B．travelled

C．has travelled

People ________ smoke in a public place may have to pay 500 yuan as a punishment

A．what

B．who

C．which

Could you tell me ________ during Earth Hour on Mar．31st this year?

A．where were you

B．what you are doing

C．who you stayed with

Her mother always persuades her ________ her diet properly．

A．to reduce

B．not to reduce

C．reduce

Parents around the world ________ worried about children playing too many video games．

A．is

B．was

C．are

An expert team ________ to study H7N9 bird flu virus in April, 2013．

A．is set up

B．was set up

C．has set up