E-books E-books (1) ... (2) ... a few decades but recently they (3) ... more popular with
readers. The first e-books (4) ... technical
manuals or specialized documents that only
a few people (5) ... interested in. In recent
years, novelists (6) ... their books online and
the contents of some of the best libraries
in the world are now in cyber archives. A
few years (7) companies like Sony and
Amazon (8) ... e-readers to make it easier for
people to read e-books.
1 a) existed
b) have existed
c) has existed
2 a) ago
b) for
c) since
3 a) have become
b) have became
c) became
4 a) was
b) have been
c) were
5 a) was
b) have been
c) were
6 a) published
b) have published
c) has published
7 a) just
b) since
c) ago
8 a) invented
b) have invented
c) have invent

E-books have existed (1) for a few decades but recently they have become (3) more popular with readers. The first e-books were (4) technical manuals or specialized documents that only a few people were (5) interested in. In recent years, novelists have published (6) their books online and the contents of some of the best libraries in the world are now in cyber archives. A few years ago (7) companies like Sony and Amazon have invented (8) e-readers to make it easier for people to read e-books.

1. The correct answer for the first blank is "a) existed." We use the past simple tense because it refers to the time when e-books were first introduced.
2. The correct answer for the second blank is "b) for." It indicates the duration of time, which is a few decades.
3. The correct answer for the third blank is "a) have become." We use the present perfect tense because it refers to the recent past until now.
4. The correct answer for the fourth blank is "b) have been." We use the present perfect tense to describe something that started in the past and continues until now.
5. The correct answer for the fifth blank is "c) were." We use the past simple tense because it refers to a specific point in the past when only a few people were interested in e-books.
6. The correct answer for the sixth blank is "b) have published." We use the present perfect tense to show that novelists have published their books online in the recent past until now.
7. The correct answer for the seventh blank is "a) just." It means a short time ago.
8. The correct answer for the eighth blank is "b) have invented." We use the present perfect tense to show that Sony and Amazon invented e-readers in the recent past until now.