八年级英语下册Unit5GrammarFocus教学课件人教版.ppt

While he was walking, a taxi came. He was walking when a taxi came.
Both of them mean
Are they the same? No ！！！
when and while “当……的时候”
when
when引导的时间状语从句可以表示一个时间点, 也可以表示一个时 间段。从句中可以用短暂性动词，也可以用延续性动词。 It was snowing when we got to the airport.
我们到达机场时， 天正下着雪。 My key dropped on the ground when I was walking in the park.
我在公园散步时， 钥匙掉在了地上。
while
while引导的时间状语从句常指一个时间段，从句中的动词 常为延续性的。while有时还可表示主句的动作与从句的动 作同时发生。 While he was reading, the phone rang.
What were they doing when it began to rain?
They were playing computer games when it began to rain.
They were playing chess when it began to rain.
They were playing football when it began to rain.
While Jake was sleeping, what did his brother do? He played basketball.
When Jake was sleeping, his brother played basketball.
While they were dancing, what happened?
他正在看书时，电话铃响了。 Some students were reading while others were writing.
一些学生在读书，另一些学生在写字。
when 和 while 的区别
1) 若从句是一个短暂性动作，主句是一个持续性动作，可用 when 但不用 while：
It was raining hard when we arrived. 我们到达时正下着大雨。
__s_t_o_le__ (steal) his car.
5. While we _w_e_r_e_w__a_it_i_n_g_ (wait) for the bus, a girl _w_a_s__r_u_n_n_i_n_g_ (run) up to us.
6. I _w__a_s_p_h_o_n_i_n_g_ (telephone) a friend when Bob _c_a_m__e__ (come) in.
Translation
1. 当开始下雨的时候，我正和朋友们在操场上打篮球。 I was playing basketball with my friends in the playground when it started to rain.
2. 我当时甚至不知道我正在做什么。 I did not even know what I was doing at that time.
2) 表示主、从句正在进行的动作或状态的对比时多用while： While she was making a phone call, I was writing a letter.
3) when 可用作并列连词，表示“这时(突然)”，但while不可以； while 可以用作并列连词，表示“而、却”(表示对比)，但when没 有这种用法。
7. While mother _w_a_s__m_a_k_i_n_g_ (make) the bed, the door bell __r_a_n_g___ (ring).
8. We _w__e_r_e_t_e_st_i_n_g_ (test) the new machine when the electricity __w__e_n_t__ (go) off.
3. 当我妈妈在做晚饭的时候，我在卧室做作业。 I was doing my homework in the bedroom while my mother was cooking supper.
4. 当我今天早上看到她时，她正急匆匆地赶去上班。
When I saw her this morning, sheห้องสมุดไป่ตู้was in a great hurry to go to work.
(write) a letter. 3. While we _w__e_re__h_a_v_in__g_ (have) a picnic, it _s_t_a_r_te_d___
(start) to rain. 4. While John _w__a_s_s_le_e_p_i_n_g_ (sleep) last night, someone
While they were dancing, the telephone rang. When the telephone rang, they were dancing.
He was singing when the baby started to cry. While he was singing, the baby started to cry.
We were about to start when it began to rain. He likes coffee, while she likes tea.
1. I __w_a_s__w_a_t_c_h_in_g__ (watch) TV when she _c_a_l_le_d__ (call). 2. When the phone __r_a_n_g__ (ring), she _w_a_s_w__r_it_in__g_