1 . (2018·全国Ⅱ)Corn production has jumped nearly 125 percent over __________ past 25 years, while rice has increased only 7 percent.

2 . Of ________ nineteen recognized polar bear subpopulations，three are declining，six are stable，one is increasing，and nine lack enough data. (用适当的词填空)

3 . When your meet with annoying things in your life, your parents are often ______ first targets of your anger.（用适当的单词填空）

4 . In January, 2017, Trump was elected ______ president of the USA, ______ position he will hold for 4 years.

A．a; a

B．/; a

C．the; a

D．the; the

5 . My new classmate told us about his trip to ______ Great Wall. He said it was _______ exciting experience for him.

A．the; an	B．不填; the
C．the;不填	D．不填; a

6 . In 1768, ________ commander of the Endeavour, James Cooks, met Joseph Banks, who was appointed ________ president of the Royal Society 10 years ago.

A．/; /	B．/; the
C．the; the	D．the; /

7 . It was ___struggle for him to finish _______experiment, with the room in ________mess after he finished it.

A．the; an; /	B．a; the; a
C．a; an; /	D．/; the; a

8 . When armed with ______ awareness of what you truly value, you are in ______ excellent position to pick a career you will find rewarding.

A．an; an	B．the; an
C．an; the	D．the; the

9 . Hunger is _____ number one global health risk, so the WFP has organized a lot of programmes, which helps people most at ________risk.

A．the； /	B．a； /
C．the；the	D．a；a

10 . In the Olympic Games, swimming is __________ second __________ importance only to track and field event.

A．the；to	B．/；to
C．the；in	D．/；in