It ______ him over 10 years to work on his one-man helicopter and at last he succeeded.
A. spent B. cost
C. took D. paid
Investors are also concerned that once the economy improves, people might lose ______ interest in further education.
A. 不填 B. a
C. an D. the
It won’t be long ______ self-driving cars appear on the market.
A. until B. after
C. when D. before
From 1902 to 1904, Picasso, the twentieth-century’s greatest western artist, painted a series of pictures _______ the main color was blue.
A. when B. that
C. where D. which
The more I think about him, the more reasons I find for loving him _______ I did.
A. as much as B. as long as
C. as soon as D. as far as
Reduce it ______ half each month and before you know it, you will not be thinking of it anymore.
A. to B. by
C. in D. for
