Measure word 些
些 is a measure word showing indefinite quantity. It is usually used after demonstrative pronouns such as 這, 那, 哪 and after the numeral 一:
一些
some
這些
these
那些
those
哪些
which (plural)
Don't attempt to mix 些 with definite measures. It is wrong to say 這些三本詞典 (these three dictionaries); one can only say 這三本詞典.
是 . . . 的 construction
Earlier we saw the construction with simple nouns, pronouns or adjectives:
這本書是中文的。= 這本書中文的書。
那條裙子是妹妹的。= 那條裙子是妹妹的裙子。
姐姐的大衣是黑的。= 姐姐的大衣是黑的大衣。
But the 是 . . . 的 construction can also be used with prepositional phrases and even whole verbal constructions:
那些點心是給丁雲的。= 那些點心是丁雲的點心。
Those pastries are for Ding Yun.
這束花兒是我給她買的。= 這束花兒我給她買的花兒。
This bunch of flowers is the one I bought for her.
這本書是我在大學的圖書館借的。= 這本書是我在大學的圖書館借的書。
This book is the one I borrowed from the university library.