1.commentary ①N-VAR A commentary is a description of an event that is br...

1.extract ①V-T To extract a substance means to obtain it from something ...

1.integral ADJ Something that is an integral part of something is an ess...

1.porch ①N-COUNT A porch is a sheltered area at the entrance to a buildi...

1.reproach ①V-T If you reproach someone, you say or show that you are di...

1.unprecedented ①ADJ If something is unprecedented, it has never happene...

1.alternate ①V-RECIP When you alternate two things, you keep using one t...

1.elapse V-I When time elapses, it passes. (时间) 流逝 • Forty-eight hours h...

1.converge ①V-I If people or vehicles converge on a place, they move tow...

1.ascertain V-T If you ascertain the truth about something, you find out...