The phrase "broke down . . . barriers" means ________ .
A.disclosed opportunities
B.shattered obstacles
C.revealed inaccuracies
D.analyzed destinations

The word "eventually" could best be replaced by which of the following?
A.later
B.at last
C.in the long run
D.recently

What is the main topic of this passage?
A.the nature of radar
B.types of ranging
C.alternatives to radar
D.history of radar

The word “dense” could be replaced by __________ .
A.cold
B.wet
C.dark
D.thick

Which of the following words best describes the tone of this passage?
A.argumentative
B.imaginative
C.explanatory
D.humorous

Which type of waves does radar use?
A.sound
B.heat
C.radio
D.light

A.prevent
B.patient
C.medicine
D.pleasant

A.global
B.love
C.lonely
D.local

This is my tenth year working in this bank.
A.By the end of this year, I will work in this bank for ten years.
B.I have worked in this bank for ten years by the end of this year.
C.By the end of this year, I will have worked in this bank for ten years.
D.I had been working in this bank for ten years by the end of this year.

Jane refused to attend his birthday party, which made him feel sad.
A.Jane’s refusal to attend his birthday party made him feel sad
B.Jane made him ad despite her refusal to attend his birthday party
C.He felt sad not to be able to attend her birthday party.
D.Jane refused to attend his birthday because it made him sad.