By menunjukkan sebuah batas waktu untuk terjadinya sesuatu – sebuah peristiwa harus terjadi sebelum waktu tertentu dicapai. Contoh:

• You need to finish this report by Monday.
• I’ll be back by six o’clock.
• Our business will be making a profit by next March.

Ada tiga frase umum yang digunakan bersama dengan by:

By the time

• I want to be a successful businessman by the time 1′m 30.
• By the time we arrive at the station, the train will be gone.

By then

• They have four months to prepare for the soccer game, so by then they should be a strong team.
• The deadline for giving your essay is next Monday at 4.00. If I don’t receive your essay by then, it won’t be marked.

By that time

• We finished work at 9.00, but by that time it was too late to go out.
• I hope to go abroad next year, and by that time I’ll have enough money.

2. Untill

Until berarti sebuah tindakan atau situasi terus berlanjut sampai waktu tertentu. Contoh:

• We were working last night until 2.30.
• You can stay at home until you feel better.
• Can you wait until I’m ready?

Coba bandingkan until dan by:

• “I’ll work here until September.” Ini berarti pembicara akan bekerja disini sampai September, kemudian berhenti.
• “I’ll work here by September.” Ini berarti bahwa pembicara tidak sedang bekerja disini sekarang, tetapi baru akan memulai bekerja pada waktu antara sekarang sampai September.

Till

Till merupakan bentuk lain dari until, maknanya secara umum sama walaupun until biasanya digunakan pada awal kalimat.

3. From…to/until

From…to/until digunakan untuk menandai permulaan dan akhir sebuah periode waktu. Contoh:

• Western people often work from Monday to Friday, but Oriental people often work from Monday to Saturday.
• I’m staying in Saudi Arabia from the beginning of March until the end of August.

From…to sedikit lebih informal dibanding from…until.

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Rujukan:
http://www.1-language.com/englishcoursenew/unit48_grammar.htm