半固体培养基中,琼脂使用浓度为固体培养基中,琼脂使用浓度为。
—— Dad, I ________ the station for minutes, but nobody came to meet me.—— Don’t worry. I’ll go to meet you soon.
A. arrived at
B. have been at
C. will reach
D. am reaching
Echo _____ for half a month. She’ll come back in two months.
A. left
B. leave
C. has left
D. has been away
When I got to the station, then train ______.
A. left
B. had left
C. leave
D. will leave