Unit 19　Modern agriculture

sf:fertilize:rice growers fertilize their fields by flooding them with water.
fertilization:proper fertilization is important for farming.
sg:inform:he informed them of his arrival.
information:the information might be false.
sh:protect:it is our duty to protect our country.
protection:the protection of our country is the duty of us all.
si:modify:adjectives modify nouns.
modification:the article needs some modification.
step ⅲ.grammar:the use of “it”(2)
t:(teacher shows some sentences on the screen.)
look at the two groups of sentences on the screen:
     
t:are sentence a and b in each group have the same meaning?
ss:yes.both of the two sentences in each group have the same meaning.
t:are there any difference?sa,can you tell me?
sa:yes.sentence a is the emphatic form,while sentence b is normal.am i right?
t:yes,you are right.“it is/was…that…”is the emphatic construction.this structure can be used to emphasize almost any part of the sentence (except emphasizing the verb).besides,if we emphasize the subject,“who”(referring to a person)is possible instead of “that”.if an object is emphasized,“whom”(referring to a person)is possible.look at the screen.read this sentences and rewrite them,emphasizing the parts underlined,using“it is/was…that…”.please prepare them in pairs.
rewrite the sentences:
1. the children often help the father and mother do the farm work.
2. in 1993,a tomato was developed that was very different from any grown before.
3.the biggest problem of chinese farmers is the shortage of arable land.
4. the plants grown in greenhouses are protected from the wind,rain and insects.
5.future agriculture should depend on high technology as well as traditional methods.
(after a few minutes.)
t:are you ready?(ss:yes.)please change these sentences.one student,one sentence.who will be the first?
sb:i'll try.sentence 2:it is the children who/that often help the father and mother do the farm work.
sc:i want to rewrite the second sentence,but i'm not sure whether i should use“is”or“was”.
t:here you should use “was”.
sc:sentence i:it was in 1993 when a tomato was developed that was very different from any grown before.
t:is he right,sd?
sd:yes.
t:you're both wrong.we should pay special attention to “that”when we emphasize the adverbial of time and place.in both situations,we should use“that”instead of “when ”or“where”.are you clear about that?
ss:yes.
t:let's go on with the other sentences.
se:sentence 3:it is the shortage of arable land that the biggest problem of chinese farmers is.