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1．This is an (apple/apples).
2．There are many (child/children).
3．These (box/boxes) are big and heavy.
4．How many (man/men) are there in the store?
5．The (potato/potatoes) is on the table.
6．This girl is (sing/singing).
7．The old man (is/are) crying sadly.
8．Do you see (a/an) "s" in these words?
9．These words (go/goes) with an "es".
10．Show me some (photos/photo)!
同类型试题
y = sin x， x∈R， y∈[–1，1]，周期为2π，函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x， x∈[–1，1]， y∈[–π/2，π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2
y = sin x， x∈R， y∈[–1，1]，周期为2π，函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x， x∈[–1，1]， y∈[–π/2，π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2
