Key調(diào):

why do we call it a "sonata in C major" ,or say that "it's written in the key of C"?
Most people would answer that music is "in a key" when its tones relate to one central tone(the one that has the same nme as the key)and when the functions of the other tones results from the keys in which they relate to the central one.
According to this answer ,the Morart Sonata is in C because C is the central tone;we hear the other tones as subordinate ([s?'b??d?n?t]附屬)to C.

The Tonic主音:

Word：prominent突出的 bars小節(jié)（線） downward向下的 subsequent 后來的sixteenth-note 十六分音符scales音階 repeat重復(fù) generalizing from總結(jié)
We can state that the tonic,the central tone of the key,forms the point of departure (出發(fā))from which the other tones move and the goal to which they are directed.
主音（調(diào)的中心音），不僅是其他音移動(dòng)的出發(fā)點(diǎn)（the point of derarture），并且也是其他音朝向的目標(biāo)。

Word:pieces contain包含subordinate從屬的tonal ['t??n(?)l]音調(diào)的consecutive連續(xù)的 [k?n'sekj?t?v] symbol ['s?mb(?)l]標(biāo)志abstraction抽象的cap加蓋，帽子throughout貫穿始終pitch音高
For the most part the pieces would contain the tones C,D,E,F,G,A,and B,and any other tones would paly a subordinate role.
別的C大調(diào)的樂曲也都會(huì)包括CDEFGAB,并且別的音都扮演著從屬/次要的角色。
When all the tone that belong to a key occur in consecutive order ,each one next to those closest to it in pitch,the result ia s scale.
當(dāng)所有的屬于一個(gè)調(diào)的音按照連續(xù)的順序來排列，音高相鄰的音排列在一起，結(jié)果就是音階。
1:Tonic.2:supertonic.3:mediant.4:subdominant.5:dominant.6:submediant.7:leading tone。

word:register ['red??st?]音域 indicate equivalent相等的
The beginning and ending tones of Example 1-4 are both C,but they are not one and the same tone.The last tone sounds considerably(非常的)higher in pitch than the first.Yet ,despite this marked(明顯的) difference in register, the sounds of two C's are very similar,that's why we call them both by the same letter name.When two tones are separated by an octave they are equivalent-----that is ,they are variants(變體) of the same sound.
This phonomenon of the octave ['?kt?v] equivalence is one of the most important aspects of pitch organization in music.In technical writing about music,it is frequently helpful to indicate the register in which a tone occurs.
這個(gè)八度等音調(diào)現(xiàn)象是音高組織中最重要的概念之一。在音樂寫作中，它對(duì)指出音所在的音域非常有幫助。
其實(shí)是說我們學(xué)過的小字一組，大字組.....都是根據(jù)八度劃分界限和分組的。（猜測(cè)WHY小字1組是c是因?yàn)閏正好在高音譜號(hào)的第一線/個(gè)）
小字一組（c1）：one-line.二組：two-line..... 小字組（低音c）：small.大字組：great.再低大字一組（C1）:contra。大字二組：sub-contra

adjacent 相鄰的

The distance between one tone of a scale and the next is usually called a step級(jí)/階.
The scale from C to C contains two kinds of steps: small ones betwwen E and F and betweenB and C,larger ones between the other adjacent tones. we call the smaller steps half steps(semitones)h半音 and the larger ones whole steps(or whole tones)w全音.

applied V and VII副屬和副導(dǎo)
Any major or minor triad ['tra??d] may be preceded[pr?'si?d] by an applied V or VII(tirad or seventh-chord).
When the cross relation is between adjacent[?'d?e?s(?)nt]鄰近的 upper voices in the same register.
In sequences模進(jìn) with descending 5ths,a chainl鏈子，連接一串 odf applied chords is possible連續(xù)下行,each sounding like the dominnant of the next.