标准尺寸的三脚架可能会不便于使用，用于拍摄低角度的物体时尤其如此。Full-size tripods can be awkward, especially if you'reshooting a low-level subject.各种外形和尺寸的自行车都有。Bikes come in all shapes and sizes.标准尺寸的斯诺克球台a full-size snooker table...
有许多种氨基酸人体自身不能合成.There are many amino acids that the body cannot synthesise itself.有许多种氨基酸人体自身不能合成。There are many amino acids that the body cannot synthesize itself.丙氨酸在转氨作用中似乎是更好的氨基酸.Alanine appears to be the preferred a...