题干

下列各组物质中,前一种物质由分子构成,后一种由原子构成的是(    )

A:氯化钠、镁

B:二氧化碳、水

C:水、汞

D:氧气、氮气

上一题 下一题 0.0难度 选择题 更新时间:2019-08-08 09:46:25

答案(点此获取答案解析)

C

同类题3

阅读下面短文,用括号内所给动词的适当形式填空(必要时可加情态动词或助动词)。
    “Everything happens for the best," my grandmother said whenever things weren't going my way. "Don't worry, one day your luck ____ (change). "
    Grandmother was right, as I discovered after graduating from college. I had decided to be sports announcer (广播员) in a radio station, so I ____  ( go) to Shanghai and knocked on the door of every station. But I got refused every time.
    In one station, a kind lady said my problem was short of experience. " Get some work with a small station and ____ (work) your way up ," she said.
    I couldn't get a job there, either. Then my dad told me a businessman had opened a company and needed someone ____  ( manage) the sports center. But again, I didn't get the job.
    I felt really down. "Your luck will change," Granny reminded me. I tried another radio station in Beijing. But the owner, a nice man, told me he already had someone.
    As I left his office, I asked, " How can someone be a sports announcer if he ____ (not, get) a job in a radio station?"
    I ____ ( wait) for the elevator when I heard the man call, " What was that you said about sports? Do you know anything about football?" I ____ (put) in front of a microphone and asked to imagine I was commenting (评论) on a football game. "Now you ____ (watch) the football game between Lu Neng and Shen Hua. . . "
    On my way home, Granny's words came back to me, " One day your luck will change, boy. And when it ____ ( happen) , it’ll feel twice as good because of all the disappointment (失望) you ____  ( have) . " At that moment I knew just what she meant.

同类题5

阅读下列短文,从每题所给的A、B、C、D四个选项中,选出最佳选项。

A Language Programme for Teenagers

Welcome to Teenagers Abroad! We invite you to join us on an amazing journey of language learning.

Our Courses

Regardless of your choice of course, you'll develop your language ability both quickly and effectively.

Our Standard Course guarantees a significant increase in your confidence in a foreign language, with focused teaching in all 4 skill areas----speaking, listening, reading and writing.

Our Intensive Course builds on our Standard Course, with 10 additional lessons per week, guaranteeing the fastest possible language learning (see table below).

Course Type

Days

Number of Lesson

 Course Timetable

Standard Course

Mon-Fri

20 lessons

9:30-12:30

Intensive Course

Mon-Fri

20 lessons

9:30-12:30

20 lessons

13:30-14:30

Evaluation

Student are placed into classes according to their current language skills. The majority of them take on online language test before starting their programme. However, if this is not available, students sit the exam on the first Monday of their course.

Learning materials are provided to students throughout their course, and there will never be more than 15 participants in each class.

Arrivals and Transfer

Our programme offers the full package—students are take good care of from the start through to the very end. They are collected from the airport upon arrival and brought to their accommodation in comfort. Werequire the student's full details at least 4 weeks in advance.

Meals/Allergies(过敏)/Special Dietary Requirements

Students are provided with breakfast, dinner and either a cooked or packed lunch (which consists of a sandwich, a drink and adessert). Snacks outside of meal times may be purchased by the student individually.

We ask that you let us know of any allergies or dietary requirements as well as information about any medicines you take. Depending on the type of allergies and/ or dietary requirements, an extra charge may be made for providing special food.