The maple leaves had fallen and they lined the gutters of the asphalted streets.枫树已经落叶,铺满了柏油路两旁的阴沟.He installed rain gutters and downspouts.他安装了雨水檐沟和排水管。The gutters either side of the paved high road were gurgling and ev...
In covalent bonding, atoms share electrons.在共价键联中, 原子共有电子.Crystals may be classified as either ionic or covalent by analogy with molecules.与分子的情况一样,晶体也可以分为离子键型和共价键型.Ceramics primarily have ionic bonds, but covalent bondi...
The indefatigable Walters was in his element.精力充沛的沃尔特斯真是得其所哉.His indefatigable spirit helped him to cope with his illness.他不屈不挠的精神帮助他对抗病魔。His indefatigable spirit helped him to cope with his illness...他不屈不挠的精神帮助他对抗病魔。He ...