第1个回答 2019-10-28
1)表示以一般的方法或方式。如:
No
one
in
those
days
could
live
by
writing
poems.
(2)表示传达、传递的方式或煤介。如:
How
did
you
send
the
letter,
by
airmail
or
by
ordinary
mail?
(3)表示用交通工具、通讯工具后接名词单数,不加冠词。如:
He
came
by
train,
but
his
wife
came
by
bus.
注意下面两句的区别:
Did
you
come
by
train?
Did
you
come
in
his
car
/
on
my
bike?
“by
+抽象名词”构成的词组有:by
accident
/
by
chance
/
by
diligence
/
by
effort
/
by
force
/
by
heart
/
by
luck
/
by
mistake
/
by
hard
work.
将来完成时用来表示在将来某一时间以前已经完成或一直持续的动作。经常与before+将来时间或by+将来时间连用,也可与before或by
the
time引导的现在时的从句连用。
1)
构成will
/
be
going
to
do
sth.
2)
概念
a.
状态完成:表示某事继续到将来某一时为止一直有的状态。
b.
动作完成:表示将来某一时或另一个将来的动作之前,已经完成的动作或一获得的经验。
They
will
have
been
married
for
20
years
by
then.
You
will
have
reached
Shanghai
by
this
time
tomorrow.
将来完成时的构成
将来完成时的构成是由"shall/will
+
have
+过去分词"构成的。
Before
long
he
will
have
forgotten
all
about
the
matter.
不久他就会全然忘记这件事的。
He
is
somebody
now.
He
will
not
have
remembered
his
old
classmates.
他现在是一个有身份的人了,他可能不会记得老同学了。
Will
you
have
known
Kevin
for
10
years
next
month?
到下个月你认识凯文该有10年了吧?
将来完成时的用法
①表示在将来某一时间之前已完成的动作,并往往对将来某一时间产生影响。
We
shall
have
learned
12
units
by
the
end
of
this
term.
到这个学期末,我们将学完12个单元。
By
the
time
you
get
home
I
will
have
cleaned
the
house
from
top
to
bottom.
你到家之前我将把房子彻底打扫一遍。