At the heart of a comer's coma lies a nucleus of solid material, typically no more than 10 kilometers across.
/ P* |! p1 f! p2 _( D. Q; yThe word "heart" is closest in meaning to which of following?
! ^5 O7 U3 \% c8 v(A) center* d8 ~2 z3 K+ K
(B) edge7 F0 q! {: d" r9 Z
(C) tail5 |; U- Z% Z! Y/ Z# g6 x: M
(D) beginning$ U8 a- H1 J- E
! \' m& ?+ p/ r5 p! [
The most graphic proof that the grand spectacle of a comet develops from a relatively small and inconspicuous chunk of ice and dust was the close-up image obtained in 1986 by the European Giotto probe of the nucleus of Halley's Comet.8 x- ~& ~" p; i% g
The word "graphic" is closest in meaning to which of following?2 W+ j) }+ b% |- m8 x
(A) mathematical2 b2 A' @# t* P& Q" W
(B) popular
( H3 g% ^$ K1 W, k: @. r(C) unusual7 B0 o* n8 q& n; h( a
(D) vivid$ ^% u- M% o' y. W
* R z5 t: q9 c403. As a comet's orbit brings it closer to the Sun, first the coma grows, then two distinct tails usually form.
; A5 [4 M1 ~3 N# r: BThe word "distinct" is closest in meaning to which of following?0 y6 f9 J q5 y3 |' P2 Y
(A) visible
# [' S9 B# g% u7 C% q" {(B) gaseous
b. A; E6 j B1 L# r(C) separate
& ?' N3 V3 V# @1 E; Y(D) new
- A& D* [0 s! H4 l* z. E& A$ \$ `# r9 a
. Pheromones are substances that serve as chemical signals between members of the same species.
m7 O, ]( q9 R9 iThe word "serve" is closest in meaning to which of following?% Q5 K$ Y: r2 i" p4 @5 h& {+ v
(A) improve
/ e$ v; W6 w; m1 V$ p* K6 Y2 `' g(B) function, s* s/ ~0 X1 H! `! }7 A) q
(C) begin
) M3 _4 Q8 y# ~% m9 W(D) rely
4 W% f+ X' {4 U* J* }3 ]
^6 g) P) `" K0 t. Z- h7 k9 o3 B. Pheromones are the predominant medium of communication among insects (but rarely the sole method) . Some species have simple pheromone systems and produce only a few pheromones, but others produce many with various functions.- {1 q0 J4 P, U. d: @- \
The word "sole" is closest in meaning to which of following?
# y- {/ m7 _2 ]/ c7 q(A) obvious
+ W9 Y) T0 M, D+ t( D(B) best1 h9 D6 J1 P0 p9 I; e' b$ U
(C) only6 W+ A" S! E' i m: Q8 N" s! e$ V
(D) final6 @. j* W$ n& R
ADCBC |
发表于 2012-8-14 22:41:43
