According to the planning of Changsha's construction of Dahexi River, the Municipal Tourism Bureau plans to build the West Lake Ecological and Cultural Park in Xianjia Lake. As shown in the figure, the design scheme adopts the peninsula in the lake. (Ⅰ) ,

(Ⅱ)

(I) Let the shoreline of the lake be L, the vertical line pass through point A and point B respectively, and the vertical foot is point E and point F, extending from point AB to point G. ..

Because BC = 2 and BCF = 60, then,

Because CD = x > 1, DF = CD-CF = x- 1,

Therefore ... (3 points)

Because ∠ ABC = 150, ∠ CBG =30, and ∠ BCF =60,

Then ∠ BGC =30, so.

Because ab =, then ag = ab+BG =,

So AE = agsin 30 =, Ge = agcos 30 = 6.

And GC = BC = 2, then ce = ge-GC = 4, because CD = x < 4, then de = ce-CD = 4-x,

So ...? (7 points)

(Ⅱ) Let ∠ ADB = θ, then

( )。 (9 points)

Let x+2 = t, then.

Because, then, if and only if, that is, when the equal sign, so when, that is, when, tan θ takes the maximum value.

And θ is an acute angle, θ takes the maximum value. ? (12)

Therefore, when the sightseeing pavilion D is built at a distance of C, the visual effect of viewing the sightseeing belt AB at D is the best. (13)