A.just,already & yet
just和already位於過去分詞之前 We've just come back from our holiday.
yet位於否定句或疑問句的句末 Has your course started yet?
B.for & since
用於表示某事開始於過去,並一直持續到現在。
for用於表示這段時間有多長 for about three years.
since用於表示這段時間開始於何時 since thursday,I think.
A.just,already & yet
just和already位於過去分詞之前 We've just come back from our holiday.
yet位於否定句或疑問句的句末 Has your course started yet?
B.for & since
用於表示某事開始於過去,並一直持續到現在。
for用於表示這段時間有多長 for about three years.
since用於表示這段時間開始於何時 since thursday,I think.