经纬仪是测量()的仪器
A. 水平角
B. 竖直角
C. 可以间接测量高差
D. 身高
I tried to _________them down to their promise, but I failed.
A. ask
B. tell
C. nail
D. knock
Nobody but Jack and Tom ________ in the office yesterday.
A. are
B. was
C. were
D. have been
They nodded ________each other in greeting.
A. to
B. for
C. in
D. up