In English conditional sentences, the condition clause (protasis) is a dependent clause, most commonly introduced by the conjunction if. Other conjunctions or equivalent expressions may also be used, such as unless (meaning if...not), provided (that) , providing (that) and as long as.irst conditional or conditional I refers to a pattern used in predictive conditional sentences, i.e. those that concern consequences of a probable future event (see Types of conditional sentence).
Lesson Summary [edit]. 1  Mechanical weathering breaks existing rock into smaller pieces without changing the composition of the rock. 2  Ice wedging and abrasion are two important processes of mechanical weathering. 3  The main agents of mechanical weathering are moving water, wind, glacial ice and gravity.
CHAPTER 11: WATER AND ENERGY Physical weathering Weathering How is a large mountain broken down into tiny grai ns of sand? The process of breaking down rock is called weathering (Figure 11.3). Physical weathering Physical forces may break or chip rocks into smaller pieces. This process is called physical weathering. Physical weathering may break large blocks loose or chip away tiny grains, one at a time. Liquid water Liquid water is a physical weathering agent. Rocks break up