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.
building and volcanic activity. At the same time, external processes continually break rock apart and move the debris to lower elevations, as shown in Figure 1. The breaking down and changing of rocks at or near Earthâs surface is called weathering. Weathering is a basic part of the rock cycle and a key process in the Earth system. There are two types of weatheringâmechanical and chemical. Though these processes are different, they are at. work at the same time. Figure 1 Weathering Ice, rain, and wind are slowly breaking down the rock in this mountain.