, to be .
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| to be | + noun | A current is the motion of charges.(- , , , , . to be ) |
| + preposition + noun | He is at the computer now. ( , , . to be .) | |
| + Ving | He is speaking on the phone at this moment. ( Continuous Simple Continuous Perfect ) | |
| + Ved | The theory of electromagnetic waves was described by Maxwell. ( Past Participle ) | |
| + to V | He is to come here tomorrow. ( to , ) |
TO BE
| With Subject | Form | |
| Base | be | |
| Present Tense | I | am |
| He, she, it | is | |
| We, you, they | are | |
| Past Tense | I, he, she, it | was |
| We, you, they | were | |
| Future Tense | I, we | shall be |
| He, she, it, you, they | will be | |
| ing-form | being | |
| Past Participle | been |
| Full positive form | Contraction | Full negative form | Contraction |
| I am | Im | I am not | Im not |
| He (she, it) is | Hes | He (she, it) is not | He isnt |
| We (you, they) are | Were | We (you, they) are not | We arent |
| I (he, she, it) was | I was | I (he, she, it) was not | I wasnt |
| We (you, they) were | We were | We (you, they) were not | We werent |
| I (we) shall be | Ill be | I (we) shall not be | I shant be |
| He (she, it, you, they) will be | Hell be | He (she, it, you, they) will not be | He wont be |
Do not (Dont): Dont be angry. .
Dont be late. .
1. to be , ?
1. A conductor is a material having free charges which move under the influence of an electric field. 2. Either changes of current can be shown graphically. 3. The state of the problem was shown in this article. 4. Electrons which are relatively free of atoms are called free electrons. 5. The power of an output signal of an amplifier is much higher than the power of its input signal. 6. An electromagnetic wave is invisible.
2. to be Present Simple (am, is, are), Past Simple (was, were), Future Simple (shall be, will be). , to be .
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1. The free charges in an electrolyte ____ positive and negative electron.
Present Simple
2. A crystal oscillator _____ a screening chamber containing a quartz crystal. Present Simple
3. Electrons _____ particles that form a part of all atoms. Present Simple
4. The first computers ___ for single users only. Past Simple
5. Next messaging ____ the smart way to communicate. Present Simple
3. to be Present Continuous (am doing, is doing, are doing), Past Continuous (was doing, were doing), Future Continuous (shall be doing, will be doing).
1. An electromagnetic wave is invisible traveling at the speed of light. 2. An electromagnetic wave is carrying information from a transmitter to a receiver. 3. The division between minis and macros is now disappearing.
4. to be , Passive Voice
1. After heating the cathode, the electron emission from its surface is produced. 2. The four states of matter are known, they being: solid, liquid, gas and plasma. 3. Solid-state devices are made of semiconductor crystals. 4. Silicon and germanium are found to be the two well known materials in the manufacture of crystal devices. 5. The normal work of silicon semiconductor devices can be guaranteed at temperatures of the -40 C to + 125 C range. 6. Different means is required to reduce noise in radio systems. 7. The characteristics of semiconductor and vacuum diodes can be represented as mathematical equations. 8. The free electrons in materials are held within the bounds of the materials by surface restraint. 9. The valve production is connected with evacuation processes. 10. Valve characteristics must be paid great attention to. 11. The tetrode was operated as an amplifier under certain conditions. 12. The effect of a secondary emission was accompanied by other changes of valve characteristic. 13. Collisions between electrons can be neglected.
5. to be , , , ,
1. The function of the transmitting station is to modulate the carrier wave and then radiate it for the purpose of reaching the receiver.
6. :
1. A: I have a Physics exam tomorrow.
B: Oh dear. Physics is/ are a very difficult subject.
2. A: My office is three miles from my house.
B: Three miles is/ are a long way to walk to work.
3. A: My little brother has got measles.
B: Oh dear. Measles is/ are quite a serious illness.
4. A: Jane looked nice today, didn't she?
B: Yes. Her clothes were/was very smart.
5. A: I've got two pounds. I'm going to buy a CD.
B: Two pounds is/are not enough to buy a CD.
6. A: The classroom was empty when I walked past.
B: Yes. The class was/were all on a school outing.
7. A: Have you just cleaned the stairs?
B: Yes, so be careful. They is/are very slippery.
8. A: Did you ask John to fix your car?
B: Yes. His advice was/were that I take it to a garage.
9. A: Did you enjoy your holiday?
B: Yes, thank you. The weather was/were wonderful.
10. A: These trousers is/are very old.
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B: You should buy a new pair.
7. .
1. there/ types/ of unit crystal patterns/ are/ many?
2. materials/ used to produce/ what/ commonly/ are/ a good thermionic cathode?
3. the work/ is/ function/ what/ of the tungsten?
4. the main/ disadvantage/ is/ what/ of the oxide cathode?
5. is/ the difference between/ what/ a diode and a triode?
6. the total energy/ is/ what/ of the electron equal to?
7. can/ be/ electrons/ made to move/ how/ inside a bulb in a fairly unimpeded manner?
8. are/ usually produced/ charge carriers/ how/ in a crystal sample?
9. are/ where/ potentials/ in a valve applied?
10. are/ why/ to be used/ chemically inactive gases/ for gas-filled valves?
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